Renault Laguna II - Strange heater/climate control problem - sally3233

Wondered if anyone might know what's up with my Laguna heater. Sometimes it works fine - I have it at about 22 and it keeps the temperature lovely. More often than not though, it will only blow out cold air unless it's on the maximum setting - 26. It's infuriating - all I can do really is leave it on 26 and then give it a blast every so often to warm the car up and then turn it back off again. Anyone know what might cause this? Also sometimes one side blows cold and the other blows warm. Would be most grateful for any assistance.

Regards Sally

Renault Laguna II - Strange heater/climate control problem - sally3233

Does anyone know what this might be?

I have since realised that it might have nothing at all to do with the actual climate control system, because even with that switched off it still only blows hot when it's on 26. So I'm thinking it's a problem with the heater itself. Anyone have any ideas please?

Renault Laguna II - Strange heater/climate control problem - elekie&a/c doctor
I would start by replacing the pollen/cabin filter.If i recall,if this becomes blocked it affects the air temp sensor operation.Worth a try.hth
Renault Laguna II - Strange heater/climate control problem - sally3233

Sorry, I should have said - the car had a full service yesterday including the pollen filter - no change with the heater :-(

Renault Laguna II - Strange heater/climate control problem - dadbif
The system is working normally, climate control maintains a constant temperature in the car (or try's to) when the interior temp exceeds the heat level you have selected it will try to lower the temperature by blowing out cold air. Logical.
Renault Laguna II - Strange heater/climate control problem - Fernando P

Seems like one of the 4 sensors that informs the automatic climate control "computer" is faulty. This hopefully could have been more precisely detected if a request had been made for that particular computer to have been interrogated when the vehicle was serviced! The 4 sensors are:- 1 the evaporator sensor located in the "heating system" and fairly easily accessible from inside the passenger side, which could well be the problem one; 2 the interior temperature/humidity sensor located in front of the interior mirror; 3 the interior sun sensor on the top of the facia panel (round press in type sensor) & 4 the exterior temperature sensor - the dome that is below the LHS wing mirror. Ideally the heating system computer should be read to check out the sensors. But I reckon that the evaporator sensor is the one to look at first -- and is what I would do. It is Renault part 7701048762 if you want to take a £12-13 chance! It can be changed by a reasonably competent DIY person (tricky to push in and turn etc) but if that is not for you, then skilled assistance is required.

Renault Laguna II - Strange heater/climate control problem - sally3233
Thank you, Fernando - that's very helpful. But what about the fact that the heater still blows cold when the aircon and auto buttons are both off? Does the heater system still use those same sensors even when it is acting as a standard heater?
Renault Laguna II - Strange heater/climate control problem - Fernando P

The sensors inform the computer that controls the (auto) climate control system when heat/cooling is needed. The "where" is determined by the manual selection of the temperature for each side as per the screen. If the aircon button is on you simply get aircon cooled air coming in. The heater needs to be told to operate (by the computer informed by the sensors) if hotter air is required to be mixed in, which is where the evaporator sensor comes in. There is also a "mixer" motor that blows the required hot/cool air to each side, which can be tested when the computer is interrogated. And sun heating up the fascia sensor turns down the heat/ gives colder aircon as required. But my money is on the evaporator sensor as I had the same problem and replacing this sensor cured it!

Renault Laguna II - Strange heater/climate control problem - sally3233

It all sounds very complicated to a mere female lol, but I will be down to Renault first thing Monday morning for an evaporator sensor :-) Will let you know. Thanks again.

Renault Laguna II - Strange heater/climate control problem - sally3233

I just wondered - I've noticed a buzz from the box by the rear view mirror - do you think that might be significant? I'm wondering if I should get that sensor changed first rather than the other one?

Renault Laguna II - Strange heater/climate control problem - Fernando P

Hmmm - it could well be and I think you should check this out first. Here goes :- in the box referred to, is an electric motor unit that drives a small fan that sucks an interior air sample past a sensor! The fan can easily become blocked/obstructed by fluff etc over time, which could cause a problem and maybe why a buzz can be heard from the box. If the front cover is pushed carefully forward to unhook it, the motor unit can be inspected & removed with a bit of care and the fan cleaned by a suitably skilled DIY mechanic. You can even wire it up again and see if the fan works. The motor unit (inc the sensor) costs some £52 so you need to check if it is working before you consider spending. But if you find that the fan was not operating and it works again after cleaning etc, you then need to check if the heating is working as it should because the sensor(s) may not be faulty. If you find after sorting the fan, that the heating is not working, I still reckon that step 1 is to replace the evaporator sensor. It seems a complicated system but as you wrote earlier it works well when it is all in order. And you need to get it sorted to get heating/cooling in future. The alternative is a Renault dealer computer diagnosis (of the above) and fix....!

Renault Laguna II - Strange heater/climate control problem - sally3233

Thank you so much for such a detailed reply. I've had a look at the unit and tried to get into it, but I couldn't work out how to do it. Do I have to take the rear view mirror off first, as it seems to be in the way.

Renault Laguna II - Strange heater/climate control problem - dadbif
Very interesting, with extremely detailed information, however, I still think it is normal behaviour for a climate control system, if mine starts blowing cold I just adjust the temp setting up by a single notch, it then blows hot again, until it reaches or tries to exceed that setting, whereupon it cools the cabin down again with cold air. I am sure your Renault dealer will happily sort things out for you.....
Renault Laguna II - Strange heater/climate control problem - sally3233

It definitely isn't normal - it blows cold always unless it's on 26. I either have to have very cold air blowing or very hot air blowing. Anything up to and including 25 is cold - 26 is hot - no matter what the temperature of the car is.

I'm sure my Renault dealer would be very happy to sort it out, but at £100 an hour I just can't afford it.

Renault Laguna II - Strange heater/climate control problem - Fernando P

I have had exactly the same problem as yours and fixed it myself as set out above. The way to access the motor at the rear of the mirror is to carefully (but positively) prise the front plastic forward at the top RHS and LHS of the unit where the front cover joins. You will need to insert a smallish screwdriver and turn the blade as a lever to release the cover from the clips to start it moving. It will gradually give way and and all will then be revealed. The harder bit for you will be if you have to replace the evaporator sensor, which is tricky to push and turn etc - but can be done with patience and determination.

Renault Laguna II - Strange heater/climate control problem - sally3233
Right. So today I got the cover off by the rear view mirror. The fan inside was working but it was very dusty and dirty. I cleaned it with cotton buds, but unfortunately this made no difference to my problem. I couldn't see where the sensor was in there, but I'm going to go to Renault tomorrow for an evaporator sensor, as I guess that's the next step? I might get a Haynes manual too and try to do it myself - do you think I'll be able to? Could you please tell me exactly where the evaporator sensor is, and also where the one in the rear view mirror thing is? Maybe I should change them both?

Someone I was talking to today said that it could be the actual heater unit itself or the heater matrix - both lots of money apparantly :-( I also asked my mechanic if he could do the computer thing but he doesn't have the right equipment, so if I go down that route I'd have to take it into Renault I think :-/
Renault Laguna II - Strange heater/climate control problem - elekie&a/c doctor

I,m not convinced an evap sensor will fix this.This sensor is only active when the a/c system is switched on.It could possibly be a fault with the heater matrix .A partial blockage can reduce the flow of hot engine coolant through the heating system thus reducing heat efficiency.Even a faulty engine water pump can have the same affect.(seen this many times on VW models)hth

Renault Laguna II - Strange heater/climate control problem - Fernando P

If you read my post of Sun 13 Mar 2011 21:27 carefully, it sets out what you should do if the fan is working but there is no change to the heating problem - you should replace the evaporator sensor (ES) first of all, then test out the heating again. It is highly unlikely that there is a problem with the heater matrix unless the coolant has not been changed for years and the water channels are blocked etc, which cannot be the case if you recently had heat and still get heat in the "26" setting! The good news is that if you have managed to get the cover off the motor/sensor unit by the rear mirror etc, you should be able to change the ES! It is located below the water pipes to the heater on the LSH of the air supply unit housing behind the fascia panel. On the passenger side, you unclip the plastic trim piece from the passenger footwell at the side of the centre console. The ES is about the size of a thin pencil with a flattish top, with a wiring connector that is removable, goes down a tube and is fixed by a 90' push and turn and reverse for removal. When you look at the replacement ES you will get a better understanding of what you have to do. Again, you need patience and determination to accomplish this! I think you will find that this will get your heat coming again as you need it. I would not do any more at this stage. I recommend that you get the manual referred to above especially if you are keeping the vehicle and intend to do some of your own car fixing. Finally as you have discovered, you need to have the computer interrogated by a garage that has the right "equipment" and that is the Renault dealer, although I believe some independents can obtain the software package required.

Renault Laguna II - Strange heater/climate control problem - sally3233
Thank you, Fernando. Having read the instructions you've given on how to change the ES, I've decided to phone Renault tomorrow and get it booked in for diagnosis. I don't feel capable of doing what you describe, bearing in mind I have no mechanical knowledge whatsoever! Once I get the diagnosis and actually KNOW what the problem is I can get my local mechanic to fix it on a nicer hourly rate than Renault! Thanks so much - I will let you know the outcome.
Renault Laguna II - Strange heater/climate control problem - sally3233

Sorry, just to add - will the fault diagnosis pinpoit the heater matrix if it's that at fault? I'm worried about spending the money on the diagnosis if it isn't going to tell me exactly what the problem is.

Renault Laguna II - Strange heater/climate control problem - sally3233
What about this - cgi.ebay.co.uk/Faulty-Air-Con-Outside-Temperature-...2
Renault Laguna II - Strange heater/climate control problem - smspencer
I'm in the centre console bit where the pipes are but can't find the sensor anywhere. If anyone happens to be online now who knows plz could they help me :-)
Renault Laguna II - Strange heater/climate control problem - sally3233
OMG FERNANDO I COULD KISS YOU!!!! I changed the evaporator sensor and it's fixed!!!!!!!!!! I can't believe it - thank you thank you thank you x
Renault Laguna II - Strange heater/climate control problem - Chuckie888

Is your Head Gasket Leaking? Is your coolant expansion tank covered in dry coolant? Does it whoosh (depressurise) significantly when you open it and then the coolant level recede?

Renault Laguna II - Strange heater/climate control problem - sebastianc

Fernando - thanks thanks thanks!

I had the same symptoms , heating on 26 deg , all other temperatures cold air.

Did change the filter , ( dirty ) but this did not help. Got the evaporator sensor- approx £12 from Renault - changed - ( took me a while to locate it) and works as a charm.

Sensor came with soft washer which made fitting close to impossible but my previous one did not have one, so removed the washer from the new one and job done)

Thanks again for great advice.

Renault Laguna II - Strange heater/climate control problem - dre_magnus

Hi all, I have exactly the opposite situation, cold air on 16, hot on all other. I believe that is also connected with the problem with external temperature sensor. Outer temperature is higher for a 7 deg, Celsius than it shows.

Another problem with climate control is that when engine goes over 2200-2300 RPM, cooling turns off. I can live with that driving in the city, but when I go on a highway in a summer it becomes unberable.

If anyone have some idea, please...

Renault Laguna II - Strange heater/climate control problem - Fernando P

If it is hot in the car ie above actual 16 deg C, the air conditioning system, when set to a 16 deg C inside temperature requirement, should produce cold air to cool the inside down to16C. Could be that the outside temp sensor is faulty/has a bad connection, given the disparity of readings you have described. You either pay up and have the air conditioning system computer read for any faults by a Renault dealer (and have them fixed?) or if you are a competent DIY mechanic and think that removing the NS mirror glass would not be a problem for you, take a chance and replace the sensor, part No 7700773858, at a cost of ~£25 - according to the link above.

Renault Laguna II - Strange heater/climate control problem - Andrew Thomas

Hi dre_magnus Reading through these posts I found yours with the same problem I have on my Laguna 2005 air con which switchs off the cold air over about 2200-2300 revs, only ambient then flows, and comes back when I slow down .Did you ever solve this , I have just had a new pressure switch fitted but no difference, the system is charged,etc. Hope you are still out there or anyone else that can help.

Renault Laguna II - Strange heater/climate control problem - MartMan
Fernando

I have the same problem can you tell me where the polen filter is and where the sensor is, is it in the mirror or in the sun roof control box.

Thanks
MartMan
Renault Laguna II - Strange heater/climate control problem - Fernando P

Which problem are you referring to? Why do you think that the pollen filter, located in a plastic housing behind the glove compartment, is causing a problem? As an aside, it should be renewed at 18K miles or more frequently anyway. I have explained in an earlier post (March 2011) where the sensors are located but need to be clear about the problem before I consider which sensor(s) might be involved.

Renault Laguna II - Strange heater/climate control problem - MartMan
Fernando

Thanks for getting back

The problem is that both the air con and heating only work at 26 degrees it was fine two weeks ago during a long trip.
I have no recollection of the polen filter ever being changed.
I've read that the sensor somewhere near the rear view mirror can get blocked or just fail but I am unsure as to it's location.

MartMan
Renault Laguna II - Strange heater/climate control problem - Fernando P

My post of Sat 12 Mar 2011 11:11 above covers the evaporator sensor, which is what I reckon you need to change given the information you have just provided. If you read on a bit more, you will find out about the interior temperature sensor that you refer to, which is located behind the rear mirror!

Renault Laguna II - Strange heater/climate control problem - MartMan
Thanks

Will let you know the outcome.

Do you know any thing about parking sensors, mine stopped working about a year ago, for a while I would get the occasional squeak but I don't even get that now.

MartMan
Renault Laguna II - Strange heater/climate control problem - wailim1972

Hi Fernando,

My parents Laguna heater acting up although not quite the same symptoms as above.

In their case, the fan motor only come on after a delay. Could be 5 seconds or could be just after you reverse out of the drive, or it might not come on at all that day! Also, when it does come on, it will blow warm air on passenger side to feet, face or screen as required but only cold air to all three levels on drivers side.

I think the heater motor resister may be failing and 1 or more blend door or mixer actuators has failed. What do you think? I've heard they are nigh on impossible to get at in Laguna without removing the dash... any idea?

Ta

Renault Laguna II - Strange heater/climate control problem - Fernando P

It is normal for a delay when the climate control system is switched on because the computer needs to evaluate the information from the sensors before the system can operate as required. Given the symptoms you describe, I believe your diagnosis that the mixing flap motors are not working as they should, is correct. I think you will have to face up to a Renault Service Centre (RSC) CLIP computer test to hopefully determine exactly what the problem before you try to fix it. BTW some RSCs make a reduced labour charge if the vehicle is over a certain age. The way to access the "heater" is to remove the card reader from the fascia, the heating control panel and then the trim panels from the footwell. But this is a task for an experienced DIY mechanic.

Renault Laguna II - Strange heater/climate control problem - MartMan
Fernando

Thanks

The heating is now working, I was able to remove the cover complete with sensor and fan without any tools. I was unable to remove the plug must be a security tab somewhere but due to its location I was unable to see. I removed the sensor assembly from the hosing and with a small art brush removed the dust and fluf from the sensor and the fan. The fan is not as noisey now and the heating is working.

Do you know any thing about parking sensors?

MartMan
Renault Laguna II - Strange heater/climate control problem - Fernando P

Good - another satisfied reader of "Technical Matters"! You must have strong hands btw. The plug can be removed by releasing the catch that keeps it in but the fan and sensor can be cleaned without being removed. I hope that the heating is working as it should because the symptoms you described pointed to an evaporator sensor failure.

Regarding the parking sensors, I guess that selecting reverse switches on the parking aid system and the first step is to have a look around the gearbox, which you have not given details of, to see if the wiring/connection is ok. Are the reversing light(s) ok? Fuse F4 (20A) is the one for the parking aid + reversing lights etc. There are also the parking aid control unit connections to consider.

Renault Laguna II - Strange heater/climate control problem - MartMan
Fernando

Thanks for getting back
The reversing lights are fine as there were a view squeaks from it before it totally stopped working I'm guessing that it's the control unit. Do you have any idea where they hide these things, it's a factory fit. I have also heard that the wiring on each sensor can come lose/break do you know how to remove the sensors for inspection?

MartMan
Renault Laguna II - Strange heater/climate control problem - Fernando P

1 In the boot.

2 The wiring to (most of) the sensors can be seen from behind the bumper. You might just be able to remove 2-3 sensors without removing the bumper to gain proper access to them.

Renault Laguna II - Strange heater/climate control problem - mukiwa

Can anyone advise me please? I've read all the posts I can find and not found a solution to my problem.

The climate fan on my Laguna always runs at max speed when on auto. It starts slow when the car is first started and then builds to max as the engine warms up, and then stays there.

I have cleaned the temperature sensor behind the mirror which was awful and replaced the pollen filter which wasn't too bad.

I've also replaced the climate computer. Not to solve this problem, but because the backlight had failed for the third time, and I couldn't solder it again and because it would suddenly set the temperature to 16 or 24 without being touched and the driver's temperature setting dial wasn't working properly when turned.

Changing the temperature each side and changing which vents are used manually, works fine. I'm satisfied that the mix motors and vent motors are functioning as they should.

However, sometime the air to the drivers footwell feels cooler than the air on the dash vent.

And further advice gratefully received.

Edited by mukiwa on 04/03/2013 at 12:55

Renault Laguna II - Strange heater/climate control problem - Fernando P

1) What temperature is set for each side? 2) When the fan continues on max, does the interior heating match the temperature that is set ? 3) Does the temperature need to be set to the max < 26c to get heat coming? 4) When the drivers footwell feels cooler, is it sunny at the time? 5) Do you know if the motor (fan) is operating for the int temperature sensor behind the mirror? 6) Did the fan slow down, say to setting 3, in the past? 7) When the heating is run on manual, do you get the right amount of heat coming out? PS Not sure why you started a new thread of correspondence in the middle of it all!

Renault Laguna II - Strange heater/climate control problem - henry balmforth

Hi Fernando or anyone else that can help!

I've been reading your really helpful advice, and wondered if you would be able to help us please. A week ago we bought a 2007 Renault Laguna 2.0 DCI, with only 49k on the clock. It started fine this morning, but when I tried to start the car at lunchtime it just clicked and wondered turn over. It had a new battery put on it 6 months ago, so I looked to see what else was wrong and I found that the 100amp starter motor fuse had gone. I had noticed a couple of other issues, for example when I put the wipers on the first setting it did one slow wipe and then went on full speed, also the heater blower stopped working when the big fuse went. Do you think this could be connected? I've done some online research, and I'm not sure if the 100amp fuse was big enough. Do you know what size it should be? I've replaced the fuse to get it started, but as the heater blower has stopped working I'm not sure what to do next. I would really appreciate your advice. Thank you,

Renault Laguna II - Strange heater/climate control problem - Fernando P

You need to check the appropriate handbook for the fuse sizes including the fuse for the heater blower. Also check that charging is correct. You should get ~ 14.4 volts across the battery terminals when charging is taking place. Is the starter motor faulty in some way? .

Renault Laguna II - Strange heater/climate control problem - enor
Hello all I same problem with my heater it was working fine now it blowing a small amount of air though but no power.

I have changed the cabin filter with no change to the heater.


Can somebody offer me some advice please ?
Renault Laguna II - Strange heater/climate control problem - dave216072

Hi Fernando P,

Not sure if you still use this site still as thsi post was some years agao now, but having read your posts on here regarding the heater control (or lack of) I bought and fitted a new Evap sensor as I had the same issue of all heat on or all cold on no in betweens. It has sorted it right out.

The fitting was not so straight forward as I have shovels for hands, but managed it eventually. It took me about 20 minutes as struggled to get the old one out.

I just thought I would send you a message and thank you for your advice, as I spoke with Renault and they quoted about £345 plus VAT to check and sort out teh problem as it could be a number of things.

Again thank you and all the others here for asking the questions etc which promted your responses and I hope you all had a gr8 Xmas and New Year.

Thanks again,

Dave.

Renault Laguna II - Strange heater/climate control problem - dj8work

Hey Fernando you seem to be the name to ask...Can you help me with my heating related problem? When i turn my car on and switch on the heating nothing happens. No hot air, no cold air... nothing! Even the fan isnt working. Doesnt matter when setting i have the heater unit switched too.

Renault Laguna II - Strange heater/climate control problem - Fernando P

1 What car do you have the heating problem with? 2 If it is a Laguna 11 does it have auto climate control? 3 If so is the LCD display operating as it should? 4 Was the heating working as it should up until now? 5 Anything happen that may have resulted in the failure you describe? 6 Is the appropriate fuse OK?

Renault Laguna II - Strange heater/climate control problem - dj8work

1 What car do you have the heating problem with? 2 If it is a Laguna 11 does it have auto climate control? 3 If so is the LCD display operating as it should? 4 Was the heating working as it should up until now? 5 Anything happen that may have resulted in the failure you describe? 6 Is the appropriate fuse OK?

Its a Laguna 2002 automatic. The Climit controll works well the LCD shows its working all light are on etc.. The heating was fine untill yesterday and nothing happened that may of caused it. I did think about the fuse but i couldnt locat which one it was? Is the fuse in that pannel on the drivdrs side dashboard?

Renault Laguna II - Strange heater/climate control problem - Fernando P

The interior fuses are located behind a panel on the drivers side dashboard that is revealed when the drivers door is opened. The engine compartment fuses are located beside the battery. F4 (20A) is the one for the heating system.

Renault Laguna II - Strange heater/climate control problem - dj8work

The interior fuses are located behind a panel on the drivers side dashboard that is revealed when the drivers door is opened. The engine compartment fuses are located beside the battery. F4 (20A) is the one for the heating system.

So the dashboard panel fuses are irrelevant to my problem, I should be looking for F4 next to the battery, rite?

If the fuse isnt the issue i should take a look at the Fan motor located under the passenger side footweld and bench test it with a 12v battery?

Renault Laguna II - Strange heater/climate control problem - dj8work

The interior fuses are located behind a panel on the drivers side dashboard that is revealed when the drivers door is opened. The engine compartment fuses are located beside the battery. F4 (20A) is the one for the heating system.

Just had a quick look but i couldnt find that F4 fuse.. But i did find out that the fuse also runs supplys Parking assistance - Alarm + after ignition feed information - Lighting controlled by electric locks - Rain sensor - Heated windscreen. And all of them work. So would it be safe to say the fuse is ok?

Renault Laguna II - Strange heater/climate control problem - starquake

i had the same problem some months ago. i've tested all fuses, relays, etc, but everything was fine. so finally i measured my battery that had a voltage just below 12 volts (about 11.5V or so). i've charged my battery fully, and next day everything was fine. the fluid levels in the original factory battery were very chaotic, so i decided to buy a new battery, and had no similar problems ever since. hope this helps.

Renault Laguna II - Strange heater/climate control problem - bozidar.krizan

I read this thread and I think I have a very similar problem...

My dual-zone air conditioning, heating one side, the other is not heated.

I ask your opinion.. Thank you!

I m from Croatia.

Renault Laguna II - Strange heater/climate control problem - Fernando P

If your vehicle (Laguna 11 ?) has automatic climate control: if the temperature for the cold side is set for heating and no hot air is being blown out, the mixer motor for that side may be faulty.

Renault Laguna II - Strange heater/climate control problem - bozidar.krizan

It is a Laguna II, yes.. I will take the climate control unit and check the motor...

Thank you!

Renault Laguna II - Strange heater/climate control problem - eddie.eagles

Although my car is a renault vel satis all the componenets I believe are the same. I have the same problems with the climate only blowing out cold up to 25 then hot at 26. However, the aircon is not working. I have changed the evap sensor, no joy for either problems. Also put a new pollen filter in. All other sensors seem normal and working, had them all off and cleaned etc.

I took it to get regassed at kwik fit, but still no joy, air compressor does not kick in but light still comes on at the control panel (I know this is just a light). They said it only had 75g in the system so was empty and filled it the required level of 650 (There might be a decimal point in there somwehere!

They put a diagnostic on the car and it said "compressor coupling open circuit" which they believe is at the air compressor pump but they were not sure. unfortunately it did not give the renault code.

The centre of the aircon pump turns freely but I nor kwikfit could get to the connector on the pump. I am at a total loss what to do, have tried everything. Do i take it to an aircon specialist, or renault (When i win the lottery!) or a diagnostics service or ideally resolve the problem myself. Fernando, if you are still on here you the sound like the man who would know.....

Renault Laguna II - Strange heater/climate control problem - Laguna2004

Hello,

I am having a similar issue and wonder if anyone has any thoughts. I have a 2004 Laguna with automatic heating / climate control. Starting the car in the morning everything is lovely then after say 20 minutes the driver’s side goes gradually cold before having no heat at all. Changing the temp to 26 degrees is the only way to get heat back. I have changed the following already:

  • Mixing Motor
  • Pollen Filter
  • Engine Temperature Sensor
  • Sensor behind the rear view mirror

I am now at a loss as to what would be wrong and appreciate some advice. Considering the heating works fine for the first half an hour (this morning it went cold after going around a roundabout) I am thinking it is more likely to be a sensor issue. Does anyone have any thoughts on this?

Thanks,

Renault Laguna II - Strange heater/climate control problem - Fernando P

My above post of Sat 12 Mar 2011 11.11 (etc) explains about changing the evaporator sensor, which is what I believe you need to do. I dont believe that any of the changes you have made so far were necessary to solve this problem - as was evidenced by the outcome!

Renault Laguna II - Strange heater/climate control problem - Laguna2004

Thank you for replying so quickly. I have read all the posts and the next thing to try was changing this sensor. Having changed the mixing motors I don't see that being an issue. I am however slightly confused as to how the evaporator works.

My normal setup is push auto, push the air recirulation twice so the light goes off then push air con twice so the auto light goes off and the air con will never come on. The system still changes the vents etc as one would expect. In this instance because the air conditioning is not engaged, will the evaporator sensor be doing anything? Also, because the passenger side remains hot but the drivers side goes cold, could that be caused by the evaporator sensor?

Are you able to explain how the heating knows what the temp is on the drivers and the passenger considering there's only one sensor behind the rear view mirror?

Thanks again for your help.

Renault Laguna II - Strange heater/climate control problem - Fernando P

An explanation of the heater controls is set out in the handbook for the vehicle. In summary, to let fresh air, in you set the RHS control so that the red light is on the RHS position and leave it thus all the time. To set the auto climate control, you set the LHS control so that the red light is on and leave it thus unless you wish to revert to manual operation. The air con (red light) then somes on/off as required. You select the air temperature required for each side by adjusting the controls accordingly. Explanation about the function of the sensors is in my above posts. From what you have reported, my diagnosis is that this is a classis case of a faulty evaporator sensor.

Renault Laguna II - Strange heater/climate control problem - Daba

Hi!

I am new here. Searched the net in despair...

I have a Laguna II and the strange problem with A/C. I've been to the Renault service center and I'll tell you their diagnose after I discribe the problem.

First time I noticed the problem was when driving. I could feel when the compressor has been turned on and off, every couple of minutes. It was like slight decrease in power but noticeable. A/C light remained lit all the time!

Tried to detect the problem when stationary and I couldn't. A/C system worked OK as I checked it with the thermometer.

After some time conditons deteriorated further to the point that it didn't matter if the vehicle is stationary or not. A/C would start to cool and after a couple of minutes switched the compressor off. A/C light remains on all the time. Then after another couple of minutes it will switch the copressor back on and start to cool for a minute or two. Then all over again...

Renault service had a bit of a headache with the diagnostics and finally they telephoned me and said that it seems the "controls" are faulty. It will cost me around 600-700 euros and a month or two waiting for delivery from France.

Alternatively they can override the "controls" but then the compressor would then work all the time on 100% power which is not advisable (according to them).

This all seems fishy to me.

Please be kind and advise me what to do. It is not a problem for me to be a DIY mechanic. Even a bit of your lengthened arm electric/electronics guy.

Thank you very much in advance!

Daba

Renault Laguna II - Strange heater/climate control problem - Pete24

I have a laguna 11 with air con and the blower now only works on low speed, believe this could be something to do with the resistor pack. I have removed this from the airflow (has a blue base), is anyone aware of a repair for this part?

Renault Laguna II - Strange heater/climate control problem - Fuzzfeatures

Sounds like resistor. Ebay is your friend here. make sure you get the right part number tho. If you have the climate control youll need the part number 52485218. Sorry, I'm not sure how to replace it tho - my problem turned out to be knackered fan :)

Renault Laguna II - Strange heater/climate control problem - cashul

Hello!

I see you guys are really the most close to my problem that I have found on the internet, so if anyone still here, Fernando, could you please help me ?

I have a Clio 2 and the problem is as follows: I can`t change the temperature. It blows hot air when on maxi, any other setting leads to kind of cold air, and I can only change from values by setting a temperature on the screen, then stop engine, restart engine. If I try to change temperature while enginge running screen displays right but temperature doesn`t change at all.

Thanks in advance...

Renault Laguna II - Strange heater/climate control problem - Gunaman

Hi all,l had this exact same problem with my 07 Guna and following advice on the forum have finally fixed it.

A/c now working as it should.However,l must report l had much difficulty in finding the evorative sensor,l was advised to change.So l thought l d try and give a bit more info on it.

The Evap sensor is tucked in about half way up the unit mounted behind the centre console.It is toward the bulkhead end.you will feel a lip that is the 2 halves of the casing which encose the unit,which is about 20 mm wide,the sensor is just above this and once found is relatively easy to extract and replace by turning it 90 degrees

it must go back in the way it came out,there are 2 small plastic locators on it,one is smaller than the other,so you must put it in the right way.

I had a problem with turning it when l put it back in and found l had inadvertantly doubled up on the rubber washers,the old one still being stuck in the housing.

Paid $66 dollars for this bit of plastic but it worked.

Now l have something else to report about this,when l first changed the sensor,it seemed to have very little effect,so l went back on the web and found something advising to disconnect the battery for 15 mins by the negative terminal.It was only after l did this that it finally worked.

So now l really dont know if it was this or the sensor that cured the problem,so l would suggest trying this first.

O and cleaned the sensor in front of the rear vision mirror,l did this first,it was indeed a bit dirty but this appeared to have no effect.

Anyway,thanks for the posts Fernando,a great help.

Renault Laguna II - Strange heater/climate control problem - Fernando P

I am pleased that the advice helped you Gunaman. I am not sure, however, that it is necessary to disconnect the battery to get things working.

Renault Laguna II - Strange heater/climate control problem - Gunaman

Thanx again Fernando,this is exactly what happened.I changed the sensor but after driving for a while still could not get the a/c to work properly,so l tried disconnecting the battery for about 20 mins.After that the a/c worked perfectly.Maybe it resets the control module or something?

Renault Laguna II - Strange heater/climate control problem - globalste

My problem is slightly different. I have a '03 Laguna 2 with climate control, about a month ago I managed to fix the lighting display thanks to a fix on the renault forum, the car works mostly fine, the air conditioning has had it though as the compressor leaks so its just non-conditioned air.

This week, the car has suddenly decided not to pump out warm air. I get cool air only, both sides and for any combination of vents. I have checked the pipes behind the glovebox and they are stone cold.

I took the climate control box out of the centre and took it apart to check for loose wires (the blue wires can be a bit dicky on these) but that hasn't resolved it either. I am certain its not a blockage as I had heating the other day and now I have no heating.

Current thought process is:

1) Buy a climate control unit from Ebay, £20.

2) Evap sensor that Fernando mentioned

3) CLIP diagnostics

I am slightly apprehensive about the evap sensor for a couple of reasons, one I still can't figure out where on earth it is located. But two, I notice that everyone who has replaced the sensor had some form of heating, eg at 26C it would provide something. My climate provides nothing at all. However, when I adjust the climate from 26 to 16, I can hear the flow mixers adjusting and the rate of air through the system increases, when adjusting back to 26 I can hear the mixers adjusting back and the flow rate decreases.

I think the pipes from the engine are warm, however I am not 100% certain that I am checking the correct ones, but I've checked any that go into the bulkhead both stainless and rubber/plastic.

Any help much appreciated.

Renault Laguna II - Strange heater/climate control problem - Fernando P

You need not do any of the above as it sounds like coolant is not getting through to the heater matrix. First of all you need to ensure that the header tank is properly topped up. Then, looking in from the front of the engine to the bulkhead (nearside), you will find the 2 coolant flow and return pipes to the heater matrix. There is an air bleed valve at the top of the nearside pipe which needs to be checked for air in the pipe when the engine is hot. There are other air bleed valves to consider depending on what happens when you action the above.

Renault Laguna II - Strange heater/climate control problem - globalste
Thanks for the tip, topped up the coolant to the max and then bled the pipe which bubbled away. Red hot air flowing through now!

Took about 8 bleeds leaving the engine running over about an hour

Many thanks!

Edited by globalste on 04/11/2015 at 15:36

Renault Laguna II - Strange heater/climate control problem - Fernando P

You are welcome. Next, you need to do the same to the bleed valve similar to a tyre air valve cap, at the thermostat, located to the nearside of the engine looking from the front. And if you have a 2.2dCi engine there is another bleed valve at the off side top of the radiator - again when the coolant is topped up and the engine hot. You might also have a think about why the coolant got to such a low level. If it goes down again soon, you may well have a leak problem to contend with.

Renault Laguna II - Strange heater/climate control problem - globalste
Will have a look for those, I didn't notice them in the Haynes manual when I had a look for any other bleed valves. I imagine that there is a leak of some sort, it was pretty low, but I don't remember the last time the header tank was checked if I'm honest, it's stained and gives the illusion of having fluid in it when it's actually empty :-/

Yes it's a 2.2dci

Edited by globalste on 05/11/2015 at 20:52

 

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