C5 Automatic Headlights & Remote Central Lock

[shaggygareth]

Hi,

Firstly Im new so I'll introduce myself, My name is Gareth, I'm 39 and from Lincoln. I was the proud owner of a Citroen C5 2003 VTR Diesel Estate. She has 185,000K on the clock, Head Gasket and Belt done at 178,000 clutch at 150,000

I registered because I need help solving a problem, that neither my Local Citroen dealer nor my regular garage can agree what the fault is.... So I'm sorry feels a bit rude

Here goes, sorry bit of reading but i might as well be thorough.

My cabin fans only worked either off or on max, so being the clever chap i thought i was , I assumed it was the control unit, so i got another one, scraped, cut and swore an awful lot but managed to swap it over. Realised that the unit was not at fault as there was no change, and looked on here for help. Decided it must be the Heater Resistor thingy(lol) and replaced that. No problem there 2 min job. Fixed the fans . However a couple of days later the headlights (Automatic on mine) started coming on in the day, and randomly going off at night. Np I thought I'll just put them in manual mode. That fixed them staying on at night, but no matter what setting I choose, they are coming on at random in the daytime. Then the remote key fob stopped working(Or so I thought) until I realized that if I unlock the car with the key, I can then lock/unlock the car with the fob??? OK More searching on your lovely forums and google and found a BSI Reset procedure. Did that(Although there is at least 3 different ways listed) the one I used was:-

BSI Reset / Battery Disconnect / Reconnect Procedure

Did that, everything seemed to be OK no lights on in daytime, key worked. Did that for 3 days, having no issues I assumed it was OK and turned the automatic headlights back on. Now back to square one. Headlights have a mind of their own and key fob only works after key has unlocked car. A Second BSi Reset doesn't seem to have helped

Further testing reveals that the key fob works fine until the car 'sleeps' then I'm back to key to open car. Setting the headlights to manual and then turning dipped headlights on and then off again seems to allow me to drive day or night OK until again I leave the car for 10 mins then they're back.

Citroen(Actually its a Co-Op dealership) say its a faulty BSI unit and want a ridiculous amount of money.
Local garage say its either the battery or Comms 2000 unit.

Neither has used a lexia to diagnose and neither really seem to want the work. and as far as I know local garage didn't actually check the battery either.

Up until now, I have dearly loved my C5 as I have mild cerebral palsy and the automatic headlights and wipers etc etc actually help me.

[Hell Razor5543]

First, welcome aboard.

The C series are very sensitive where it comes to batteries. There is an awful lot of electronics in them, and if the battery is starting to give up all sorts of weird problems can crop up. It could be worth going somewhere like Halfords and getting the battery checked.

We have a slightly different way of resetting the BSi, which also seems to work. It could be worth a look;

Battery Disconnect / Reconnect Procedure

[shaggygareth]

Thanks for that, going to see my dad in Rugby Tomorrow so we'll give it a go and check the battery. I very much appreciate you taking the time to reply

[Hell Razor5543]

You are welcome. I hope that I am right. Just a thought; does your C5 have a battery gauge (mine does)? If it does, I wonder how accurate it is?

[daviemck2006]

Both my c5s had a battery gauge, both needed new batteries, both times I never noticed any difference on the gauges. The first one just suddenly would not start, the second one lost power steering first then wouldn't start. I really cannot recall any changes in the gauge.

[shaggygareth]

Yes it does, but its about as much use as a chocolate teapot i think? Doesnt seem to do much... Whats it supposed to be if its a good fully charged battery? Right left or middle lol

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[myglaren]

Mine have worked but there is no precision.

Recently fitted a new and larger capacity battery when the starter seized and it now shows a consistently higher voltage once recovered from a start, which doesn't take long. Is now significantly further right of centre than previously.

[shaggygareth]

Hi guys, again thanks for taking the time to reply and show an interest.

Me and my father put a multi meter on the Battery today, 14.5V Engine running, 12.5V Engine off, so at a guess its not the battery

However I've noticed something new, no idea when this started bit the Perimetric(Cant spell lol) Alarm and Central locking buttons are flashing quickly after I've locked the car? I vaguely remember reading somewhere in all my research that C5 MK1's have a big issue with After Market Head units and that was a symptom(The flashing LEDS) of an incorrectly fitted head unit.

Now if that's true, I did have to remove the head-unit to replace the fan controller. If you recall, that is when these problems with the headlights and Remote central locking started.... Have I disconnected something or dislodged a wire? I did notice a loose Black wire on the ISO lead but I was sure i'd sorted that. I also don't remember a RED wire going off somewhere for power... As I understand it that's a requirement as it should go off to a separate Ignition power lead? However my head unit works fine, including the on steering wheel controls and it remembers stored radio channels & Bluetooth connections after the cars been off.

I also didn't disconnect the battery before I took out or put back the stereo or fan control unit... Have I buggered it???

[Stickyfinger]

Have you done the battery reset as per this site yet ?...its in the Sticky.(oh I hate my name at times )

[shaggygareth]

Lol, no not as yet because i would be leaving the car unattended(as i guess most people don't actually sit there for 30mins etc) I couldnt leave it outside my house for 30mins without it or anything in it going for a walk by 'sticky' fingers lol

[elma]

Have you done the battery reset as per this site yet ?...its in the Sticky.(oh I hate my name at times )

Going to be Wiki soon, Wikifinger doesn't have the same ring to it.

Battery Disconnect / Reconnect Procedure if you need it.

[shaggygareth]

Have you done the battery reset as per this site yet ?...its in the Sticky.(oh I hate my name at times )

Going to be Wiki soon, Wikifinger doesn't have the same ring to it.

Here's the procedure if you need it.

In regards using a festoon bulb for resistance. Can i not disconnect positive terminal and leave side lights on? I know 12v is not alot but i still dont fancy doing it wrong and shocking myself

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[Hell Razor5543]

All you are doing (using the light bulb) is to gradually short out the ECUs so that any residual charge (in any capacitors) is gently lost, as opposed to discharged in a hurry, causing possible issues. There will only be 12V at a couple of amps (at most) so you should be safe. Anyway, your idea may not work, as the CANBUS system may not notice the light control if the battery is disconnected.

[elma]

I don't think leaving the side lights on will work. You could use one of the sidelight bulbs though. Don't be scared of 12v, you need at least 100v before it wants to bite you.

[shaggygareth]

Ok well i still need to do this on a driveway, so ill have to wait till Thursday.

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