Thread: Horn & Cruise Control fix

Well this was interesting and not what I expected it to be.

The CC started working intermittently and then it stopped working.

Later I noticed the horn stopped working also.

Checked the fuse - all sweet

Bought new horns, that wasn't the fix for the horns.

Swapped the relay - not the problem either.

Tested the horn buttons which were new - all good but no horn.

Earthing is good.

Shorted out the relay and boom the horns do work!

Must be the Rotary coupler behind the steering wheel - pulled the steering wheel off and it works fine.

Test out the pins in the fuse box for the fuse. All good.

Test out the pins in the fuse box for the relay. A problem.

Verdict, the earth pin, for the switching side of the relay is disconned somewhere between the fusebox and the rotary coupler.

On the wiring diagram this looks simple, look under the dash and its like that wire in the middle of a 1000 wire loom and all wrapped up tight.

Bypass surgery on the old girl with a new wire that runs directly from the fuse box on to the rotary coupler and now the horns are working

AND the cruise control is working again too! So it turns out, the CC also picks up switching "earth" from the horn circuit in the steering wheel to operate! FTW!

Originally Posted by Slunnie

....AND the cruise control is working again too! So it turns out, the CC also picks up switching "earth" from the horn circuit in the steering wheel to operate! FTW!
...

Actually the CC is picking up a reduced feed through the horn relay's coil and as you described it your problem is within that Header which for RHD is C0286(your diagram with 0291 is for a LHD vehicle) cos by connecting directly the coupler to the fusebox the CC switch is getting that voltage through the relay's coil...provided the diagram is good cos it's very strange though