One fog light staying on

Help! mate of mine has the C3 Picasso Exclusive trim 13 reg, which has the light-round-the-corner fog light thingies.

She noticed the other day that even when the car was off, keys not in the ignition, that the passenger side fog light was still on. My initial guess was that it'll be a sticky relay somewhere - but I'm buggered if I can find any flipping relays, or any reference to them on t'internet.

I have checked the middle connector in the under-bonnet fusebox, and it looks perfect, so not a corrosion issue I guess.

Turning the fog lights on turns the other one on too, but then the passenger side one stays on again when the switch is turned off.

Can anyone point me in the right direction please? and maybe tell me why the heck I can't find any ruddy relays?

Thanks in anticipation!

Hello GrumpyMike

A total shot in the dark as I don't know this vehicle, but, does the car have parking lights?

I'm thinking of the feature which many VWs have, if you leave the indicator stalk in either left or right position, lights on the corresponding side of the vehicle are on when the ignition is off.

Worth a look for nothing.

Hi Missing Lincs,

That was the thought immediately before sticky relay. From what I can glean from the handbook, this beastie doesn't have parking lights, also, there was no light showing at the rear.

Thanks for the suggestion though

There are no relays that are accessible and most of the electrical control is by solid state. The main control is the BSM module - the fuse box in the engine bay.

Thanks c3car.

So, if there are no relays, my next guess would be the switch which turns on the show-me-round-the-corner lights. Is this on the com2000, or in the steering rack?

Is it worth plugging the bugger in to lexia (or its modern equivalent) to see if it's got any grumbles?

GrumpyMike wrote:So, if there are no relays,

Not 'No relays' but not any you can change and the solid state does a job of the relay but they do get damaged too.

GrumpyMike wrote:my next guess would be the switch which turns on the show-me-round-the-corner lights. Is this on the com2000, or in the steering rack?

I would stick with the BSM - engine bay fuse box as being your problem. Yes the COM2000 does the control for lighting but not with the ignition off. Its all looking BSM.

GrumpyMike wrote:Is it worth plugging the bugger in to lexia (or its modern equivalent) to see if it's got any grumbles?

If you have lexia already, yes, plug it in to see what controls are keeping the light on, this can help prove the BSM to be faulty, but it may just be quicker? to swap out the BSM.

There are some mentions of the BSM getting damaged by a faulty screen wash motor recently, it may pay to disconnect the battery and remove all the BSM plugs and look for corrosion or water damage, even if you don't change the BSM first.

Missing Lincs wrote:A total shot in the dark as I don't know this vehicle, but, does the car have parking lights?

I'm thinking of the feature which many VWs have, if you leave the indicator stalk in either left or right position, lights on the corresponding side of the vehicle are on when the ignition is off.

This caught me out recently on a VW van, yes, I had left the indicator stalk in the wrong position

Hi C3Car.

Thank you very much for your input. I didn't realise cars had gone away from relays to what I guess will be some sort of transistor. Give me a computer to fix over a car any day!

I checked the connectors on the BSM, and they looked good.

I'll give your recommendations to my mate and see what she says.

These are a far cry from the S-reg Saxo I used to have!!!

OK. Another very related question folks.

Using the citroen service portal, and the VIN of the car, I've identified its going to be part number 6500HV. However, there don't seem to be many of them available on eBay. I have seen other suggestions on here about using 'one with a similar part number'. How am I meant to decide if it'll actually work or not? Eek!

GrumpyMike wrote:OK. Another very related question folks.

Using the citroen service portal, and the VIN of the car, I've identified its going to be part number 6500HV. However, there don't seem to be many of them available on eBay. I have seen other suggestions on here about using 'one with a similar part number'. How am I meant to decide if it'll actually work or not? Eek!

You don't find the number from the portal on ebay because its not often marked on the part.

For a BSM 6500.HV, there are other numbers marked on the unit and similar numbers of the most significant digits will be similar in function. Another way to find a suitable one is find one from the same model on the same year. But you can also cast your net to other Citroen models and even Peugeot 1007 and some 207 models - if you are matching quite close the long numbers on the box itself.

This is a suggested starting point on ebay for engine bay fuse boxes (BSM modules).

Thanks Arfur Dent.