Citroen CX Diesel Turbo - Dodgey CX Electrics

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Sat 6 Dec 2014 23:52
Citroen CX Diesel Turbo - Dodgey CX Electrics - CXTurbo2

Does anyone have any experience of tracing and locating electrical connection faults on a CX 25 Diesel Turbo 1987/8 ?

Interior Lights for example don't work - but the Plunger in the Door (which normally operates the internal lights when the door is opened), works OK as it shows a 'Door Open' message on the Dashboard Warning Indicator if the door is not closed properly. Also, the Handbrake Warning Light illuminates on the same Panel if/when the Handbrake is operated.

Also, none of the internal Light Switches work when operated manually, despite having proven the Bulbs work, when taken out and tested seperately.

Also, there are Warning Lamps missing when the ignition is switched on prior to starting the car, which normally go out if/when all is OK. If the Test Button (to the right of the Warning Lamp Strip) is pressed, all the Warning Lamps illuminate as they should, meaning the Bulbs themselves are working.

Has anybody out there got any suggestions/help/tips to track and trace the possible locations that are causing these problems ?

Any help would be gratefully received, thanks !

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Sun 7 Dec 2014 08:52
Citroen CX Diesel Turbo - Dodgey CX Electrics - daveyK_UK

Try a Citroen owners forum or write to car mechanic magazine

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Sun 7 Dec 2014 10:28
Citroen CX Diesel Turbo - Dodgey CX Electrics - elekie&a/c doctor

My first stop would be to check the fusebox for any blown or missing fuses.Have you checked for any power supply to the interior lamp fitting?Tracing a circuit on these is very difficult as there is no pattern to the wiring colours.There is usually a number printed on the wire or a coloured sleeve.

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Sun 7 Dec 2014 12:39
Citroen CX Diesel Turbo - Dodgey CX Electrics - Bromptonaut

I'd be paying particular attention to earthing points. As pointed out above wiring on these, per PSA practice at time, is for wires to be almost randomly coloured but with an identifying number printed on the insulation sleeve.

Trouble is the insulation got dirty and cleaning it could easily wipe of the number.

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Sun 7 Dec 2014 12:49
Citroen CX Diesel Turbo - Dodgey CX Electrics - dieselnut

From memory, as having owned two of these many years ago, I think the dash display is fed from the door lock switch.

The interior lights are fed from the door switch.

As someone else mentioned, sounds like you have a blown fuse for the interior lights.

Edited by dieselnut on 07/12/2014 at 12:52

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Mon 8 Dec 2014 15:49
Citroen CX Diesel Turbo - Dodgey CX Electrics - CXTurbo2

Thanks for your reply dieselnut.

However, as l mentioned in my original post, all the Door Switches are working OK, as each of them sends a warning to a dedicated Display Panel if a door is open - Front Right - Front Left - Back Right - Back Left - also if the Handbrake is on.

Fuses and Relays are all OK, they were checked and tested before l decided to Post my Question on the Forum.

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Tue 9 Dec 2014 16:16
Citroen CX Diesel Turbo - Dodgey CX Electrics - dieselnut

However, as l mentioned in my original post, all the Door Switches are working OK, as each of them sends a warning to a dedicated Display Panel if a door is open - Front Right - Front Left - Back Right - Back Left

What I was trying to say is that i'm fairly sure there is a separate switch on each door solely to operate the interior lights, it was either near the hinges or along the bottom run of the door.

The switch that illuminates the dash display is inside the door lock mechanism.

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Sun 7 Dec 2014 12:59
Citroen CX Diesel Turbo - Dodgey CX Electrics - ddavros

In the mid-90s I was crazy enough to buy a 1988 CXGti (petol) which I loved on the rare ocassions that it actually worked properly . . . (but it looked superb and dealt with speed bumps like nothing else before or since). I can still remember the gentle 'hiss' from the steering when you went round sharp bends.

As the OP has discovered, electrical gremlins are not exactly uncommon. With mine, they almost drove me to a nervous breakdown - the last straw was grinding to a hlt in Picadilly Circus in the middle of rush hour (something to do with the altenator).

However, as it turned out the root of most of the problems was exactly as diagnosed above - earthing. I don't remember the details, but I seem to recall that one or more earthing wires has corroded, causing all manner of seemingly random faults (no ignition, doors not locking, total electrical power loss, etc) which might or might not disappear after a few minutes / hours / days. The mechanic who diagnosed this used to operate from a mews just off Holloway road, but I doubt whether he's still there. Suggest you try to find a proper auto-electrician - good luck.

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Mon 8 Dec 2014 15:42
Citroen CX Diesel Turbo - Dodgey CX Electrics - CXTurbo2

Thanks for your reply ddavros.

Looks as though the consensus is tending towards earthing problems.

However, your friendly mechanic who diagnosed your earth faults might not be of use as l live in France at the moment.

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Mon 8 Dec 2014 15:37
Citroen CX Diesel Turbo - Dodgey CX Electrics - CXTurbo2

Good point Bromptonaut, so now, l will set time aside and try to locate all the Earthing Strip Connectors at their various locations in and around the Vehicle, clean them all and see what happens.

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Mon 8 Dec 2014 15:34
Citroen CX Diesel Turbo - Dodgey CX Electrics - CXTurbo2

Hi ! and thanks for your response.

I went through all the logical steps associated with Fuses - Relays, et al, but to no avail - all proved to be OK and each of the Fuse/Relay Contacts were thoroughly cleaned with switch cleaner to eliminate all possibility of corrosion. This was all done prior to posting my question on this Forum.

As it is a French vehicle, I have the Review Technique (French) Technical Bulletin & Manual (French equivalent of Haynes - Haynes don't publish a Manual for my vehicle) which has detailed schematics itentifying all the Electrics, their location/s in the vehicle, their functions and a series of illustrations showing where in the vehicle all these connections for Fuses and Relays and their associated components are located.

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Tue 9 Dec 2014 12:44
Citroen CX Diesel Turbo - Dodgey CX Electrics - Peter.N.

There is an ECU controlling the interior lights, I had one fail, I seem to remember its behind the steering column somewhere - it was a long time ago.

I had an 86 Safari CX25 DTR turbo for about 7 years and 160,000 miles, best car I have ever owned - apart from the useless heater and ammount of handbrake adjustment required.

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Tue 9 Dec 2014 23:26
Citroen CX Diesel Turbo - Dodgey CX Electrics - CXTurbo2

Thanks for your suggestion Peter.N.

I will go back to my Schematics and see if l can locate the ECU you mentioned.

The Maplight (the one that swings from left to right) in the centre of the small Roof Panel works OK. (When put back in the 'centre' position, the Maplight goes out).

The two On/Off Switches (Left & Right) located at the rear of the same small Roof Panel also work OK (the two individual lights for the rear, left and right passengers).

So, as l mentioned in part earlier, the main Interior lights will not come on when any of the doors are opened - there is, (apparently in the write-up), a time-out delay that automatically extinguishes the main interior light after a pre-determined time after all doors are closed. Does/could the ECU that you mentioned, actuate and control this function?

Regards.

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Wed 10 Dec 2014 00:00
Citroen CX Diesel Turbo - Dodgey CX Electrics - CXTurbo2

[UPDATE]

This one is just for you Peter.N.

I just dug through my French 'Controle Technique' in the car's Elecrical Section and discovered the following:

Temporisation de eclairage de l'habitacle.
L'habitacle est aclaire pendant 15 secondes qui suivant la decondamnation ou la fermeture des portes.
La boitier de temporisation est situe dans la console centrale a droite sous le cendrier.

I don't know how good your French is, but translated it reads;

Lighting timing of the cabin.
The interior is illuminated for 15 seconds after opening or closing doors.
The timeout box is located in the center console to the right under the ashtray.

So, Peter,,,,,,,your memory wasn't/isn't so bad after all.

Tomorrow, l will go 'hunting', see if this is the cause of this particular problem and get back to you,,,,!!!

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Wed 10 Dec 2014 00:31
Citroen CX Diesel Turbo - Dodgey CX Electrics - Peter.N.

That sounds about right and yes it does control the time delay on the light. Mine failed because someone had trapped on of the wires under the steering column support bracked and shorted it to earth.

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