HAZARD WARNING LIGHT

[KeithG]

Morning,
The Hazard Warning switch on my Citroen C5 Tourer is not working, directional indicators work fine. I cannot seem to find a fuse to see if that's the problem or the switch is at fault ? Any ideas most welcome!

[GiveMeABreak]

Have you replaced any bulbs with LEDs or have you attached any third party electrical devices / chargers / USB, changed the Head unit etc?

[myglaren]

They are known to corrode internally due to lack of use.
Pushing it a few dozen times scrapes off the corrosion and can start it working again.
Cheap fix if it works.

[KeithG]

Sorry for delay in getting back to you.
I have tried pressing the button several times without success .
I haven't changed any bulbs but I did plug in a phone charger to the cigar lighter sometime ago .

[GiveMeABreak]

Just watch the quality of the phone charger - some of these cheap Chinese things are not only dangerous (overheating) but can also affect the electronics if they malfunction. I always use a decent branded one or an OEM one for the car to avoid any electrical problems.

I think there was another member in a recent post that had some damage from using a faulty charger.

The Hazard switch has an earth (MC40) to the left side of the dashboard and a connection to the instrument panel and control wire to the BSI.

[KeithG]

Thanks Marc - I will buy a decent charger -didn't realise it could affect the electrics.
Can it be fixed or do I need a new switch ?
Forgive my ignorance but what is BSI ?

Keith

[GiveMeABreak]

The BSI is the Built in Systems Interface and essentially the master computer that all the other ECUs on the vehicle link into. It sends and receives commands and controls the flow of information on the data networks and keeps everything talking to each other.

Much of the equipment on a vehicle including the accessories socket has a link to the BSI - in the case of the 12V accessories sockets, the BSI has a control wire to these that can disable the power after a certain period of time as an example.

Now obviously I'm not saying your accessory has been the cause in this case - that's not possible for me to do on a Forum, but it's one of the reasons why PSA and a lot of car manufacturers caution about electrical accessories being used on their vehicles as some of these can have undesired effects on the vehicle electrical systems (which they generally mention in the owners manual).

Without further expensive electrical testing, it may be worth trying a new switch - they are about £24 (UK) from Citroen and differ for Right and left hand drive variants.

Replacement involves removing the fascia trim strip that goes underneath the centre dash vents, which exposes the bolts and clips of the fascia trim. Once this is carefully partially removed, the wiring connections are exposed behind it, so be careful. One of these will of course be the wired connection to the hazard switch module, which when unplugged leaves the module which can then be unclipped with a trim tool and removed.

Otherwise let the dealer run a diagnostic check for you and replace if necessary. The trouble with the BSI, is that if it is not one of the surrounding fuses, there is little that can be done with a BSI if it has suffered internal damage as these are more or less sealed units.

[KeithG]

Thank you Marc for such a comprehensive reply. I'll take the car to the garage !
Keith