Horn Wiring Path
Horn Wiring Path
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Discussion

schueymcfee

Original Poster:

1,577 posts

294 months

Wednesday 23rd March 2005
quotequote all
Anybody know the wiring route for the horn.

I have many cut wires under the pasenger side dash where the alarm should be and the horn isn't working.

So I was wondering if one of those wires is the horn and if so what colour?

Thanks.

spend

12,581 posts

280 months

Wednesday 23rd March 2005
quotequote all
Since you have an early car, I assume its similar to mine.

Ground --> black --> Horn Push -- purple black --> fusebox relay. (ground on control circuit)

Fuse shared between horn & interior light powers fusebox relay control circuit.

Fuse for Cooling fan is feed for horn relay switched power circuit.

Hormn relay switched power circuit -- purple white ->> horns -- black to ground

Horn Push runs in dash loom to fusebox, Horn Power runs thru passenger side wing loom.

Dave

schueymcfee

Original Poster:

1,577 posts

294 months

Wednesday 23rd March 2005
quotequote all
That's great Dave thanks.

purple/white sounds familiar, I'm sure there is a cut purple/white wire there.

Will have a look tonight

schueymcfee

Original Poster:

1,577 posts

294 months

Thursday 24th March 2005
quotequote all
Yep, it is indeed cut, but there is nothing to reconnect to just a small male plug that should've plugged into the old alarm I presume - is the wire white/purple all the way to the horn?

There are lots of other wires under there, like red/black, red/green, brown etc what do all these do?

Thanks.

spend

12,581 posts

280 months

Thursday 24th March 2005
quotequote all
Purple/white runs all the way to the horn, BVC the white-purple is something else.. in this area normally the door open signal to the timer on the aux relay panel for the heated mirrors.

If you suspect its the feed to the horns that is barfed, first check at the fusebox. If you locate pin 19 of the fusebox relay holder for the horn relay (very small writing on the fusebox moulding) and replace the relay whilst trapping a test wire you should be able to check this gives 12v when the horn is pushed (and hear relay click). Basically the back of the fusebox has a connector which the P/W wire is plugged into and it runs up the dash, to the inner wing at LHS of dash, down the inner wing to the front undertray. Mine has no breaks / connectors in until it reaches the horns.

If you established that the relay works, and you see +12v at the relay, you can start checking continuity by simply pushing a male spade terminal in that pin of the relay holder, until you find the break - well worth checking at the horn connector - just as a sanity check.

Other wires are part of the old cdl module I guess, they are shown on the diag I sent you.

Dave

schueymcfee

Original Poster:

1,577 posts

294 months

Thursday 24th March 2005
quotequote all
That's great, I'll have another look tonight.

Thanks.

schueymcfee

Original Poster:

1,577 posts

294 months

Tuesday 29th March 2005
quotequote all
Found that the purple/black wire in the steering column had been cut -

Thanks Dave you cut my diagnosis time down by about 5 hours, because I put the 12v through pin 19 on the relay to find the horns do actually worked and from then on it was easy! I also found that the wiper delay wires were cut too, so all's good now!