Horn works only when ignition is off ???

[taz]

Hoping someone may be able to help..

My horn works fine without the engine running and not at all if the engine is running.

Any suggestions as to where to look? Rip the steering column apart?

thanks in adv,
Taz.

[Phil Nottingham]

The horn on UK models anyway is direct battery fed (not through ammeter) - under the parcel shelf is a bunch of bullet coonectors for the column switch the earthed purple/black cable goes to the Horn ring collector. No relay is used but it suggests one has been retro-fitted. The horn load is far too great to go via the ignition switch

[stantondavies]

As Phil says check connections, particularly the battery earth. The horn consumes a lot of power.

[Phil Nottingham]

Reading your message again its odd that the horns only work with with the higher voltage when the engine is running. This points to a high resistance somewhere in the cable or connectors and the actual ones on horn are often the culprits. Has the wiring been messed around with.

Check the fuse box connections - battery control particularly the feed wire to the fuse

If this does not cure it it may be the horn contacts are burnes - these can be cleaned in those horns with a removeable dome otherewise its a new one - they are redailt available.

It could also be the collector ring on the steeering colomn not touching always or the contacts in the horn ring itself.

Wiring in relay is a good idea in any event

[dorsetflyer]

Phil I think you might have to untwist your knickers.
The horn works OK when the engine is NOT running, but doesn't when the engine IS running.
If the horn works then the horn ring must be OK.
So the problem is somewhere else.

[taz]

Thanks guys,
I suspect it was an intermittent fault (short) with the wire that runs from the slip ring to the spring loaded contact that mates with the horn assembly. Since replacing that wire the horn is behaving itself

Whilst replacing the wire I noticed that my saloon has a button on the left side of the steering column that also activates the horn. ...I wish I new that last week when I took the car in to be inspected for it's road worthy - they pulled me up on the horn and windscreen washer. And a loose top swivel joint. The embarrising thing was I simply did not know where the windscreen washer switch was - I was pulling back on the indicator stalk thinking that was it! The inspector must have thought I was an idiot

Oh well, I've increased the spring load on the top swivel, sorted the horn, discovered the washer switch on the side of the binickle - so I'm think I'm ready for another try

Cheers,
Taz.

[Phil Nottingham]

The simplist explanation - like reading the instructions! - is often the answer. The washer button was definitley an afterthought as MK1 had a manual floor pump. Does sound like a slip ring problem for the horm they can be very troublesome