Errant Horn

[phaeton]

Okay so now the engine is running okay(ish) the next problem stopping MOT is the horn, it likes to sound when it wants to, often turning the steering wheel, sometimes leaning on the wheel & bizarrely enough if you undo the steering column height lever. It has a relay right at the front of the chassis, I took the boss adaptor & can see 2 terminals which run on 2 rings on the back of the adaptor. Can anybody tell me if it switches to earth or switches to live & any idea what colour wire I'm looking for?

[IanS]

Early sierras (first 18 months production) switched to earth. 2 brown wires into a 2 way plug just behind the stearing wheel.

Later sierras with switch on end of indicator stalk switched the live.

Both had a relay to actually switch the horn current.

[nelmo]

I had the same setup on my steering wheel, I think - does it have 2 little springs with magnets on the end which slide round the rings? 

My magnets just never seemed strong enough to stay attached to the rings, so they kept coming off, hitting each other and sounding the horn at random times. I gave up with it and just fitted a horn button on the aux panel instead, using the wires from the column (sorry, can't remember colours).

[phaeton]

It's the older 2 wire system, spring loaded brushes running on the back of the boss adapter, there was 3 bolts holding the 2 parts of the adapter together, they were a bit long & must have been connecting with the wire at the back of the horn press. Cut the bolts shorter & added in some extra insulation, but as usual last thing to do was push the horn push back onto the housing, got it slightly wrong & broke one of the fixing legs off! So at the moment you have to press the metal strip to get the horn to work until I get a new one.