Audi A3 electrical problem - bizzare! | Technical matters | Back Room Forum

Mon 15 Jan 2007 20:19

Audi A3 electrical problem - bizzare! - Alfster

I have a 53 plate Audi A3 2.0 FSI that has developed a bizzarre electrical fault. The 'bonnet open' warning light is on (the bonnet is secure), the windscreen wash/wipe doesn't work, the screen wipers only work when the car is moving and the alarm has become super-sensitive. Also, the lights no longer flash when I lock the car using the fob, but they do when I unlock it. The rear wash/wipe works fine.

I've started locking the car with the key to disable the alarm, but the lack of wash/wipe is alarming....it's bound to be something silly, so I thought I'd ask here before Audi. Any clues anywhere??!

Thanks in advance!

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Mon 15 Jan 2007 20:57

Audi A3 electrical problem - bizzare! - daveyjp

Bonnet not closed and indicators not flashing when locked and alarm being sensitive could all be related. If any doors (including the boot and bonnet) are not closed the indicators won't flash which shows it's deadlocked.

Sounds like a possible CANBUS problem which will need a visit to the dealer. They will probably start by disconnecting the battery - could try it yourself first, but as it's under warranty why bother?

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Mon 15 Jan 2007 21:08

Audi A3 electrical problem - bizzare! - adverse camber

Are A3's subject to the same - 'water in the passenger footwell knacks one of the ecus' problem as the a4/passat etc?

the alarm and stuff to do with interiour lights / dash etc can all be relevantto the comfort ecu. lift the front passenger carpet and check if the soundproofing underneath is wet

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Tue 16 Jan 2007 10:49

Audi A3 electrical problem - bizzare! - Alfster

Thanks daveyj and adverse camber, but no luck with either. The battery disconnect didn't work and thankfully my carpets/soundproofing are bone dry. Looks like a trip to the dealer....and the car is *just* out of warranty....d'oh!

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Tue 16 Jan 2007 11:49

Audi A3 electrical problem - bizzare! - Altea Ego

The bonnet switch is badly adjusted or cream crackered. The washers/wipers on some models of VAG cars check the bonnet switch so they dont foul the bonnet if its up . The fact they work when moving along means the airflow is probaby forcing the bonnet down and making the switch, Ditto the alarm problems - it wont arm because its open circuit at the bonnet switch,
------------------------------
TourVanMan TM < Ex RF >

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Tue 16 Jan 2007 12:25

Audi A3 electrical problem - bizzare! - Red Baron

Perhaps the microswitch that engages when the bonnet is shut has a faulty connection. My Alfa has a sticky-up-thingy that gets pushed in when the bonnet is closed. I have had to stick a thin piece of rubber on the bonnet so that the sticky-up-thingy is pushed in enough. Otherwise the plip-alarm does not set properly.

Perhaps even the bonnet stop bumps at the front are set too high.

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Tue 16 Jan 2007 13:17

Audi A3 electrical problem - bizzare! - Glaikit Wee Scunner {P}

Don't worry about 'just' being out of warranty. I got VW to pay for ~ 2/3 of the total bill for a replacement ccm which got wet as a result of a leaking pollen filter. If you have got a dealer service history , speak politely to them- it has always worked for me.
My carpets did not feel wet to the touch either- guess there is a waterproof backing.
--
I wasna fu but just had plenty.

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Fri 19 Jan 2007 16:35

SOLVED!! Audi A3 electrical problem - Alfster

Thanks again for all advice. Took it to the dealer and got these results:

1. Wiper problems - all post 2003 A3s are subject to a 'proactive recall' (Audi's words) for a new wiper motor (I'd heard rumours of this)
2. Bonnet light and alarm due to faulty bonnet lock microswitch

The first is being done for free, the second they want £200 for!

I looked on EuroCarParts.com and found a new genuine Audi bonnet lock for £17.95, so I'll fit it myself. My next question is this: am I opening a can of worms? I have a standard tool kit and I'm pretty handy, but will this involve taking half the front end off first??!! Anything I need to be aware of e.g. rigging the lock? Any extra parts needed other than the lock?

Cheers.

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Sun 16 May 2010 17:53

Audi A3 electrical problem - bizzare! - coatsie

I have a 54 A3 and after the cold weather at the beginning of this year my car developed EXACTLY the same symptoms - it can not be just a coincidence that these systems all go wrong at the same time.

Could you let me know what the resolve was? The last post states that you were going to have Audi replace the washer motor and you were going to replace the bonnet latch - were there any further developments?

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Fri 4 Jun 2010 20:53

Audi A3 electrical problem - bizzare! - chrisedgar

Hi,

My 2004 A3 has developed the same problems. What was the fix, a simple bonnet switch replacement or did the windscreen motor need to be replaced too?

Kind Regards.

Chris

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Thu 6 Jan 2011 13:51

Audi A3 electrical problem - bizzare! - Alfster

Chrisedgar and coatsie, sorry that this response is so long in coming. You've probably fixed your faults by now, but yes I did get a new wiper motor fitted under recall and the dealer also supplied and fitted a bonnet catch for free. This cured all the original probs but then I had difficulty locking the bonnet as they hadn't adjusted the new catch properly. Had to go back to the dealer for a tweak but all is fine now.

Hope that's some help to somebody out there!

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Fri 14 Jan 2011 20:48

Audi A3 electrical problem - bizzare! - lisa & bill

I have just had exactly the same problem, my wipers stopped working so I tried a new wiper motor, not the problem so took it to an electrical specialist who popped up the bonnet and knew what the problem was straight away.

He said it is the micro switch, once he had bypassed it I had working wipers and they have now ordered me a new switch today:0)

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Thu 8 Jan 2015 08:50

Audi A3 electrical problem - bizzare! - Anyone

Cold weather - January 2015: my turn to have this problem.

I was interested to see "AdverseCamber's" post from Jan 2007; 2 days ago a bottle of water with a faulty lid disgorged about a pint's worth of water into the passenger footwell. That night the alarm kept going off in the wind and this morning the open-bonnet light was on and the wipers didn't work (though I did try driving and they do when the car is in motion).

I've got a heater in the footwell and I shall try the battery disconnect later.

Failing that, I shall try and find a new bonnet lock on ebay ;)

Otherwise it's off to Honest John's cousin for an under-hood tinker.

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Thu 8 Jan 2015 11:31

Audi A3 electrical problem - bizzare! - dieselnut

If it has the same layout as the A4, the convenience CCU lives at the bottom of the passenger foot well. This CCU controls the alarm amongst othe things & has wires from all doors & bonnet connecting into it.

The carpet is thick, plus it has some very thick foam under the carpet.

You need to get under the foam to dry it out or the wiring will start to corode, then wires start to break off.

The heater wont penetrate under all that insulation.

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