Sticking horn

[RichardW]

Horn: Not sure.... was that a fault from the BSI or the BSM? Either a cable fault at the back of the battery, or a BSM failure. Cable seems unlikely, what number is on the BSM under the bonnet?

Handbrake - sounds like either the cable is seized or the motor is shot - does it actually work?

[Eddie Nuff]

When I tested the motor through Lexia there was a whirring noise but

[Eddie Nuff]

The horn fault shows up in the BSM.

[Eddie Nuff]

B997 is apparently a fault code from the engine fuse box ecu saying the horn is shorting to earth. Corroded or bare wire? Poor connection at relay?

C1556 is an Electric motor control fault on the parking brake - a short circuit to either earth or positive. Could this then be causing fault code C1559 which is System locked - Electric motor, cables or calipers?

Strange that both should be an earthing issue at the same time. They aren't related surely?

Point me in the right direction please fellas. If I can sort this out it's one less plate to spin.

[RichardW]

I can't see how the horn can be anything except a BSM fault - presume the fault code is set because it is detecting that the horn is using power, but is not activated. Sadly, the BSM unit in early C4 Pics is rather expensive (now listing at £240, compared to £90 for later ones....). No doubt a breaker will turn up a cheaper one - you need to go off the number marked on it. I'd fix that first, then see about the handbrake. It could need a new primary cable - these are not too dear, and look to be not too had to fit. A new motor is ruinous....

[Eddie Nuff]

HOW MUCH!!! £240 for a piece of moulded plastic and a few relays. Stuff that I'll break the damn car first.

There is an 07 petrol being broke very near to me and an 09 diesel I know about so maybe worth a phone call.

Me not being electrically minded I'm puzzled by how the BSM can throw up a fault on the horn but nothing else. None of the other relays and fuses seem to be affected.

As for the epb if there is a short so it's not working where is the shorting problem? But when I've tested it through Lexia I can hear a whirring noise which stops and diagnostics says it cannot complete the task. That gives the assumption that the epb motor is working Need to get under and have a look whilst it's whirring away.

I did read that another epb had to be calibrated to the car and could only be done at Citroen. Any truth in that?

[ekjdm14]

I can't see how the horn can be anything except a BSM fault - presume the fault code is set because it is detecting that the horn is using power, but is not activated. ....

Not sure on this one. I can see your thinking but if the horn is, like many, negative switched and has a permanent + supply then it could still be a chafed wire shorting to earth causing it...

[RichardW]

Pretty sure it's live side switched....

[Eddie Nuff]

I was at a family do last night and got talking to a relative of my wife's who's an industrial electrician. He knows absolutely sod all about cars and has no interest in them. They're just a means of getting from a to b. But he's been working in his industry for years so I told him what the problem was and to explain, in layman's terms, what could be happening. No need for layman's terms he said, it's simple, you've got one or more chafed wires somewhere - the fun bit is finding out where

I did a bit of reading and apparently there is a loom that runs under the battery and over the gearbox which has caused this kind of greif.

[RichardW]

Some info on those wires here: http://c4owners.org/plugins/forum/forum ... ost_172026

Given how these work, I doubt that is the fault, but it will cost nothing to take the battery out and have a look!

I note earlier that Marc had found a wiring diag for yours that seemed to show it via the alarm; but service.citroen seems to indicate no alarm? It should be possible to check if you've got 12V on the wire coming out of the BSM; might be dificult to pinpoint the right one though.....

Edit: I think 12V to the horn is pin 4 on the brown connector on the BSM