Horn troubles! :doh:

My horn is very tempermantal when i have my lights on, which is quite strange! At all other times it is fine…

Does anyone know of this problem and/or how to sort it?

Thanks

:doh:

It is due to a bad connection or bad wiring I expect.  Check the condition if the wire - you'll probably find the copper had gone brown and dusty - even though you can get 12v with a meter when the current is drawn the wire warms up increasing it's resistance and reducing the voltage at the horn.

The dual horns take a lot of power and the wires deteriorate.  i've the same problem with my Black campaign.  I'm going to fit a relay controlled by the deteriorated wire as the low current will be OK and will not heat the wire.  This is a bit over kill as the horn is relay controlled anyway!  The proper way to do it is to replace the bad wires and use the original relay only.

Cheers

Rich

Engines are nasty places for electrics, mud, oil and water. And where the horn is mounted is particularly nasty. After finishing my linkage bearings this weekend I thought I would have a go at the horn as the car was on ramps and easy to get to.

Theres a couple of connectors right at the horn, I pulled them off in turn and gave them a good clean. All really full of crap.

Jobs a goodun.

Like Rich says probably a bad circuit and needs full voltage to make it work, therefore if you have the lights on it's enough of a drain to stop it working.

My rear wipers are the same, haven't got to the bottom of that one yet…

Peter.

Just rebuilt a GTI MK1, horn activation is vai a relay for the dual horns which draw a lot of power, the connctors for the horn in the lower front wing area were really dirty and the connectors them selves had oxidised quite bad, however the problem that I had was the earth wire for the steering column on the MK1 is attched to the steering rack and then onto the body, this had snapped off, hence when I was testing the horn it worked fine by pypassing the relay but would not work via the horn push on the steering wheel.

Check the spring connection under the steering wheel itself. That was causing me problems for ages but its been sorted now.

The earth wire on the steering rack is a good call to but you need an extra elbow half way down your forearm to get to the fixing!!!

Dan

cool thanx all, imma give it a bash on the weekend!

If your horn works sometimes it is unlikely to be the wire on the rack.  Listen for the relay clicking on the fuse box when you press the horn.  If this clicks when you press the horn then the problem is most likely the high current side or the relay itself.  The low current side (steering wheel column rack, dash wiring etc) will be fine.

the relay does click when its on yeah!

I had the relay replaced, which fixed the problem, until today that is…..

Bum…

what now?