C3 Electrical faults display

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Kris C3
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C3 Electrical faults display

Post by Kris C3 » 19 Dec 2011, 22:35

Hi All,

My wife's car has been giving random fault messages on the central display unit, its a 07 model with just under 40,000km's.

The first error said that the right brake light was faulty, so I replaced the bulb, the brake light still didn't work either, then it told me that all the brake lights had failed, so I eplaced the left hand brake light. Now none of the brake lights work, including the centre LED lights.

Since then the fault messages have been faulty side lamp and now the latest has been that the time and date has changed itself to 2004.

When I rang the dealership they told me that they had never heard of anything like this, which I found to be odd. So they are telling me that this is the first Citroen in the world to have such a problem?

Has anyone experienced anything similiar?? Does this mean that it's a nice easy fix, or does this mean the replacement of the ECU altogether?

Thought that I would jump on here first to see if it is a know problem, before I go into the dealership with $$ written on my forehead and being ripped off. I live in Melbourne, Australia.

Please advise.

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Re: C3 Electrical faults display

Post by citronut » 20 Dec 2011, 08:52

hi and welcome Kris

are the brake light bulbs single or double filament (stop tail bulbs ),
if so maybe one or both have been fitted in the wrong way round, this basicly shorts across the side and brake lamp terminals in the bulb holder,

or has the car got a towbar with the older type of patched in wireing, as i understand this can cause the bulb warnig to play havac,

regards malcolm

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Re: C3 Electrical faults display

Post by Sl4yer » 20 Dec 2011, 22:52

Before doing anything else, check (and clean) the connectors on the light cluster plug. Ours was throwing up similar messages the other week (all right hand side when specified) - I found that the earth pin was slightly corroded. In fact, the earth wire showed signs of having been quite hot! A quick clean later, all is well.

I wonder if yours has popped a fuse if all brake lights no longer work?

Don't know about the date reset, but nothing would surprise me with the electrics on these cars. Shame really.

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Re: C3 Electrical faults display

Post by Richard_C » 20 Dec 2011, 23:26

I can support the earth suggestion. Do check fuses and make sure you have the right type of bulbs though - its easy to mix 5w, 21w and the twin 5.21 type and get them in the wrong holes. Our C3 threw up a variety of bulb faulty messages, brake, indicator etc.randomly, and as all the bulbs were working I concluded that it was resistance in the earth return. I cleaned the contacts; the pin seemed very small for the current load when you brake and indicate with the sidelights on, total current about 4 amps. The clean up helped for a while, but now the cold damp weather is back the messages reappeared.

What I have now done is add an extra earth lead. About 50 cm of decent multi strand flex - I used a length of thick speaker wire. Drill a small hole in the plastic back of the light fitting close to the connector plug area and feed the wire through. the hole is inside anyway, and gets covered by the foam rubber ring. The uppermost bulb sits in a fairly big metal plate which connects to all the others. I cleaned up a corner of the plate, pre tinned it with solder then pre tinned the wire with the ends splayed out, then solderered it on. At the other end I created a loop and soldered that to form a ring. Next, remove the paint from a bit of bodywork inside the boot, around where the stud from the light fitting comes through. Feed the wire behind the trim panel, put it all back together with the loop end around the stud. That gives you an extra earth, much better than the puny original. As it fits aorund the stud that you have to undo anyway to get at teh light bulbs, its doesn't make it any harder to access the fitting. If you pull the rim back you will see an earth point in the boot anyway, on top of the inner wing, if you prefer to use that.

All my error messages have ceased.

The only other thoughts I have is to check where the cable to the middle brake light comes from the body and into the tailgate. Wear in insulation or a hidden crack in the conductor can cause problems (not had any C3 experience, but my SAAB 9-5 estate had a fault there).

Can't explain the 2004 reset, but that might not matter as long as everything else works. Might be a co-incidence, or maybe you have been reversing at the speed of light ..................

Current: , C4 Picasso 120 BlueHdi, C3 82 VTR+, C1 Edition
Past Citroens: Dyane (x2), 2CV, Visa, BX (x2), Xantia, Xsara Picasso, C3 1.4hdi, C5 X7 Tourer, Synergie 1.9TD
Others: Hillman Hunter, Cortina Mk 1, Maxi, VW Type 2, Granada, SAAB 900, SAAB 9-5, R5 Gordini