Weird Electrical problems - New Owner C5 X7

[deaconj999]

Hi,
I have only had my used C5 (X7) for two weeks and have a suspicion there is something odd with the electrical system, but I could be wrong.

The symptoms:

Auto lights sometimes stay on (green lights on dash on, when the two orange lights in the roof go off) after driving out of tunnels. Sometimes both go off together.

Horn was not sounding sometimes when either button on steering wheel centre console and yesterday seems to have completely failed. I have ID F2 fuse under bonnet (blue 15A) and it looks fine. Cannot find relay though.

Seat belt and passenger airbag warning light seemed to stay on for an extended time after the engine started at least once.

Do I need to reset the cars electrics using the procedure with the door window open etc ?

Any advice would be appreciated.

[Stickyfinger]

It does no harm so worth a go.

[bobins]

My first thoughts would be a BSI reset as you've suggested, and make sure the battery is fully charged as strange things happen on these cars with questionable batteries. The only other thing would be to thoroughly check the under bonnet fuse box / BSI as the early ones were known to have problems and were replaced. If yours was suspect, then it should have already been replaced by now. There was a fairly narrow window where dodgy ones were recalled - you can check for recalls here:
https://www.dft.gov.uk/vosa/apps/recall ... lt.asp?tx=

[GiveMeABreak]

It's not too clear cut from what you describe, as:
- The auto lights will sometimes stay on for a while when lighting conditions improve before shutting off and will depend on the luminosity of the light.
- The 'ambient lighting (orange lights) are located in the roof console and along the dashboard and within the doors. These lights go off when the exterior lamp warning bulbs on the dashboard instrument display extinguish.
- As for the warning lamps - the roof mounted console is for the seat belts not fastened, but there are 2 on the right hand side at the top and bottom. The bottom one will stay lit when passenger airbag has been deactivated using the key and switching the airbag off in the glovebox.
When not switched off, then the top light will light temporarily when the ignition is switched on. It usually checks everything is ok before going out.

In case you are not aware, the X7 is a CAN vehicle system with multiplexed wiring networks. Think of it as a PC - all the equipment is connected by mini computers controlled by a master brain. So be careful not to go splicing wires or adding electrical kit in without checking compatibility, as this can upset the data signals being sent down the wiring and cause problems. Like any wiring, although there is some redundancy built in for safety, wires will wear / short etc.

The X7 in common with the previous C5 models does like a good healthy battery. There is a lot of electrical kit on these cars and one of the biggest causes of electrical issues is a weak or poor battery. If the original, it will be past best by now after 9 years of operation! If changing ore disconnecting the battery always follow the battery replacement / BSI procedure.

[Paul-R]

You could certainly try it. Done properly it can do no harm.

I've never noticed the coincidence (or otherwise) between the green lights and the orange lights but I have noticed that the auto lights on the C5 work as I would expect them to in terms of switching on and off.

However the 308 lights turn on well before I would put them on in the evening and are a bit laggardly turning off after coming out of tunnels. I actually run the 308 without auto lights as a result. I reported this to the dealer when it was in for service last November but they said it was not adjustable. Well it may not be adjustable but that doesn't mean it's right.

It might be the sensor on the windscreen itself or maybe the seal between the sensor and the screen (this can cause a problem with the auto wipers) but something is wrong and I want it fixed whilst it's still under warranty. Just as I want the engine stop/start ("it's working as it should sir, the software is the latest") fixing - it's been a couple of months since it last operated. Maybe I should try the reset procedure!

[deaconj999]

My first thoughts would be a BSI reset as you've suggested, and make sure the battery is fully charged as strange things happen on these cars with questionable batteries. The only other thing would be to thoroughly check the under bonnet fuse box / BSI as the early ones were known to have problems and were replaced. If yours was suspect, then it should have already been replaced by now. There was a fairly narrow window where dodgy ones were recalled - you can check for recalls here:
https://www.dft.gov.uk/vosa/apps/recall ... lt.asp?tx=

Thanks most appreciated I will check.

[deaconj999]

It's not too clear cut from what you describe, as:
- The auto lights will sometimes stay on for a while when lighting conditions improve before shutting off and will depend on the luminosity of the light.
- The 'ambient lighting (orange lights) are located in the roof console and along the dashboard and within the doors. These lights go off when the exterior lamp warning bulbs on the dashboard instrument display extinguish.
- As for the warning lamps - the roof mounted console is for the seat belts not fastened, but there are 2 on the right hand side at the top and bottom. The bottom one will stay lit when passenger airbag has been deactivated using the key and switching the airbag off in the glovebox.
When not switched off, then the top light will light temporarily when the ignition is switched on. It usually checks everything is ok before going out.

In case you are not aware, the X7 is a CAN vehicle system with multiplexed wiring networks. Think of it as a PC - all the equipment is connected by mini computers controlled by a master brain. So be careful not to go splicing wires or adding electrical kit in without checking compatibility, as this can upset the data signals being sent down the wiring and cause problems. Like any wiring, although there is some redundancy built in for safety, wires will wear / short etc.

The X7 in common with the previous C5 models does like a good healthy battery. There is a lot of electrical kit on these cars and one of the biggest causes of electrical issues is a weak or poor battery. If the original, it will be past best by now after 9 years of operation! If changing ore disconnecting the battery always follow the battery replacement / BSI procedure.

Thanks for the detailed reply.

It is odd with the lights because coming out of a dark tunnel into daylight the orange ambient lights in the roof console go off only sometimes before the dashboard green lights x 2 go out, never have the green gone out before the orange. I have counted at least 10 seconds or more, but this doesn't happen every time. I wondered if the delay was related to this happening either a dull day or a bright sunny day such as yesterday. Yesterday, on purpose, I went through my local tunnel on the M4 in Newport, South Wales and the Orange and green lights went out at the same time. Also, upon entering tunnel both come on a the same time, every time.

I added a pioneer stereo with all the correct adaptor leads from a reputable dealer which was a matter of plug and play - no splicing or cutting took place, but I do know the horn was intermittent.

I think the airbag light staying on is normal now that it must have a built in few seconds delay. Same probably goes for the 5 red seat belt lights also.

I'm off to test the battery and continuity test on the steering column horn switches and then perform a BSI reset.

Finally, I saw a video on you tube where the steering column airbag was removed and the guy was explaining the ribbon cables could be worn which affects the horn and maybe the airbag https://youtu.be/Hsb6rUofE4I. I believe I would get a warning if the airbag was affected and a red dash light as well as a possible fault when I check the system with the [check] button on the console. So I don't believe its the airbag.

I'll post more when I investigate more as I couldn't find much on C5 Horn issues on the forum or on google.

[GiveMeABreak]

Ok, with that additional info, I would immediately suspect the after-market audio. The Citroen Head Units are not simply stereo units, they interface directly with the car systems and depending on model can be used to alter vehicle parameters / configuration, and I personally wouldn't recommend changing these, except for a compatible Citroen upgraded model. There are very few units that maintain compatibility with the car's systems (especially the steering wheel controls - of which there are many as you can see). There have been very few Airbag or horn issues on the X7 specifically to date, and I suspect that your third party interface may be causing CAN-related issues. I am also wondering whether the system was notified of the head unit removal (using Citroen Diagbox) when the after-market unit was fitted - another thing many fitters are unaware of.

Unfortunately all these issues MAY be affected by this modification, as the horn, airbag, lighting controls are controlled by communication from the control module under the steering wheel (Comms Unit) and the BSI, which link to the other ECUs. This is just another possibility as the car components and ECUs communicate via a multiplexed wiring system. Any non-compliant hardware or an incompatible wiring harness can cause electrical problems - and this will make it very hard for proper diagnosis.

[Xantippa]

Outside and interior lights do lit up and go off separately depending on daylight, so don't worry.

I had aftermarket HU on C5 X7 for many years, and it didn't cause any trouble (it was only ugly in the dash).

Bad battery caused some trouble together with fuse box. I think your car works just fine, don't worry!

[wheeler]

Auto lights sometimes stay on (green lights on dash on, when the two orange lights in the roof go off) after driving out of tunnels. Sometimes both go off together.

Strange, mines is similar, the ambient lights in the roof on mines always comes on when the headlights are switched on manually but when the headlamps come on automatically the ambient lights in the roof seem to have a mind of their own, sometimes they come on sometimes they dont.

[deaconj999]

Outside and interior lights do lit up and go off separately depending on daylight, so don't worry.

I had aftermarket HU on C5 X7 for many years, and it didn't cause any trouble (it was only ugly in the dash).

Bad battery caused some trouble together with fuse box. I think your car works just fine, don't worry!

Thanks for the comment - reassuring

[deaconj999]

Auto lights sometimes stay on (green lights on dash on, when the two orange lights in the roof go off) after driving out of tunnels. Sometimes both go off together.

Strange, mines is similar, the ambient lights in the roof on mines always comes on when the headlights are switched on manually but when the headlamps come on automatically the ambient lights in the roof seem to have a mind of their own, sometimes they come on sometimes they dont.

NIce to know I'm not on my own here, thanks !

[deaconj999]

Ok, with that additional info, I would immediately suspect the after-market audio. The Citroen Head Units are not simply stereo units, they interface directly with the car systems and depending on model can be used to alter vehicle parameters / configuration, and I personally wouldn't recommend changing these, except for a compatible Citroen upgraded model. There are very few units that maintain compatibility with the car's systems (especially the steering wheel controls - of which there are many as you can see). There have been very few Airbag or horn issues on the X7 specifically to date, and I suspect that your third party interface may be causing CAN-related issues. I am also wondering whether the system was notified of the head unit removal (using Citroen Diagbox) when the after-market unit was fitted - another thing many fitters are unaware of.

Unfortunately all these issues MAY be affected by this modification, as the horn, airbag, lighting controls are controlled by communication from the control module under the steering wheel (Comms Unit) and the BSI, which link to the other ECUs. This is just another possibility as the car components and ECUs communicate via a multiplexed wiring system. Any non-compliant hardware or an incompatible wiring harness can cause electrical problems - and this will make it very hard for proper diagnosis.

Well, just checked all the fuses with the multimeter under the bonnet fuse box. As the missus sat in the car with the ignition on the position before the car starts I got her to press the buttons for the horn left and right at separate times and together repeatedly, each time I could hear a solenoid or relay faintly clicking, this was after the suspension pump had gone quiet also- I waited for that and any other noised to cease before I got her to press the horn. I wonder if the horn is actually at fault because it did work after the stereo was fitted (by me with the recommended additional cables) or maybe as you say the pioneer stereo is not recognised by the computer. However, I have checked and all the other functions from the Steering wheel are working except for one or two like the display brightness, but it does work from the roller switch!

It would not be impossible to put the old original RD4 N2 back in and see if the horn works. I only did it because the bluetooth didn't seem to work to connect my phone. LOL

UPDATE-
Just put the original radio back in and no horn. All other functions fine as normal. When I tested the battery earlier cold it was 12.23 V and 14.XX after starting.

Should I put the new radio back in and do a BSI or leave the original in and do a BSI first to test the horn, Will a BSI reset the horn I wonder? Will it need to as it was working with the new stereo in as mentioned earlier.

How do I get to the horn as it looks hidden front left side near light somwhere I believe.

[myglaren]

Couldn't say with the X7 but mine is behind the front bumper on the nearside.

[GiveMeABreak]

Did you also put the original harness back in and reset the BSI before trying?

Re the brightness control - that's not on the steering wheel controls, it's on the speedo here at 'F' - you hold it until the desired brightness is reached, then it goes the other way.:

Here's the location of the Horn: