Horn problem

Wig

Corsa C 2003 Horn stopped working & Airbag light on
EDIT (now solved): these two symptoms can be only one thing. The steering wheel has become isolated from the electrical supply, there is an electrical joint that allows the electrical power to pass across from the steering column side onto the steering wheel. It is called a "Rotary Coupler" or a "clockspring"/"clock spring" it is also incorrectly known as a "squib" (it's not the squib, people just think that's what it is called, there is something else that is called a squib under the airbag.)

I've been reading it could be the switches on the steering wheel.

Take the airbag off and bridge the horn switch, yada yada yada...

I don't want to turn ignition on (to test the horn when bridged) when (if) airbag disconnected...

Does anyone know, is the horn supposed to work with ignition off?

Especially on this car?

Thanks.

Strider590

Yes, horns work with ignition turned off.

I would doubt the failure of two switches. If both failed then it would be a wiring issue, not the switches.

Most likely is damage or corrosion at the horn or it's wiring.

angrycrow

Strider590 wrote: »

Yes, horns work with ignition turned off.

I would doubt the failure of two switches. If both failed then it would be a wiring issue, not the switches.

Most likely is damage or corrosion at the horn or it's wiring.

Both switches could stop working if the ribbon cable (clock spring cable) is damaged. However Striders suggestion is easiest to check for first. Connect a 12v supply directly to horn and see if it sounds to rule out the actual horn being faulty.

Wig

Hi, yeah, I thought that too, unlikely for both swithches to fail.

Anyway, update so far,

I checked both switches with a multimeter they both work just fine. I checked the input wire that goes to the switches, no 12 volt supply even with the ignition on.

I am now looking into getting into the relay box, hoping to swap the relay to an identical one, (i.e. the rear number plate lamps relay or the rear wiper relay).

rich13348

Wig wrote: »

Hi,

Yeah I got jump leads, you're right I can use those, and then I only need a short bits of wire.

I actually thought about it and I could possibly come up with 2 x 2m bits of wire by stripping a bit of electrical flex, just have to find the flex... but now I like your idea better of using jump leads.

Thanks

However, I woud still need to earth it as when you pull out the plug from the horn to expose the terminals, it loses it's earth. (which was one of the 2 wires going into the horn).

However, again, I will check and swap the relay first, as I am half way through doing that, and I'm sure that is it,

You can just earth the horn through its metal casing and then touch the 12v to the space connector.

Wig

Update.

Ok
Relay is good. swapped it with the rear wiper, and the rear wiper still works.
Fuse 10 (horn) is good.

I am still to do a 12v power supply test to the horn itself, I suspect it will pass that test.

So I am left with the only indication I have of a problem, which is when inside the airbag pocket on the steering wheel... and I disconnect the connector that goes to the switches... one of those wires (either the brown or the brown/white... should be the brown/white) **should have** 12v all the time and definately when I turn the ignition. but there is no 12v.

I think it might be the steering wheel rotating contact called a "rotary joint" in the Haynes book.

The failure of the rotary joint would also explain the constant airbag light I have at the moment. because the airbag connects through the same plug. Can anyone help me to find one of these grey doughnut like connectors online?

(I started this thread concerned that turning the ignition on with airbag off would not be a good thing to do, although I already have an airbag light,,,,,I didn't want to make the situation worse,)

facade

search ebay for vauxhall corsa rotary coupler

Wig

Hi thanks,

I'm not so sure that's it now. I tested for 12v on "fuse box" side of the coupler still no 12v.
I have 12v at the No. 10 fuse
I went back to the horn relay
I bridged the relay and the horn sounded, Should have done that before!
So it is not the horn unit.

I am now checking the other circuit (the steering wheel switch circuit) at the relay for 12 volts.......because the relay appears to be between the fuse and the steering wheel in the circuit. I wish the Haynes manuals had better wiring diagrams.

Wig

angrycrow wrote: »

Both switches could stop working if the ribbon cable (clock spring cable) is damaged. However Striders suggestion is easiest to check for first. Connect a 12v supply directly to horn and see if it sounds to rule out the actual horn being faulty.

Any more info on the "clock spring cable" where I can see it , test it etc?

Do you mean the bound bundle of wires (wire harness) bound with black cloth that runs through to the steering wheel and dash unit?

I'm still trying to trace the 12v trail.

rich13348

Wig wrote: »

Hi thanks,

I'm not so sure that's it now. I tested for 12v on "fuse box" side of the coupler still no 12v.

I have 12v at the No. 10 fuse
I'm going back to the horn relay to check for 12v...because the relay appears to be between the fuse and the steering wheel in the circuit. I wish the Haynes manuals had better wiring diagrams.

I have a Haynes manual for a 2006-10 corsa and the wiring diagram shows the switch goes through the body control unit. This may not be the case on yours as it is older but its certainly a possibility. If the horn work itself works that could suggest an issue with that control module which would explain the airbag light too. Test the horn and see if it the actually sqeaker works.

facade

Wig wrote: »

Any more info on the "clock spring cable" where I can see it , test it etc?

It is the rotary coupler.
Under the steering wheel.
One half is nailed to the steering column, and the connections from the harness go in, the middle bit turns with the wheel, and the connections come out.
Inside is like a tape measure or clock spring, a flat multi conductor cable.
they have to be fitted correctly, as they cannot stand being turned more than a few degrees too much, so the middle bit has to be wound round to centre, and then the wheel put on.
A popular way to break them is to disconnect the steering rack to exchange it, and allowing someone to turn the wheel inside the car, or not refitting the rack in the same place.