Horn not working - fixed

[John]

I've had problems with the horn on my Excel for years, normally resolved by cleaning the earth on the horn button.

However, the most recent failure took me several hours to sort out - it really had me baffled. I went through the wiring methodically, and there didn't seem to be any obvious problems. The horn relay checked out fine and I could sound the horn by making an earth contact direct to the horn button connector on the relay.

That meant it had to be somewhere in the steering wheel, but all the connections seemed good. In the end it was the plunger that contacts the brass ring under the steering wheel. Mine appears to be the original, a brass pin with a screw thread on one end where the wire to the relay attaches, and a carbon pad at the other end which presses gently onto the brass ring.

There was no longer any continuity between the graphite/carbon pad and the brass pin! I removed the pad, filed the end of the brass to make it as smooth as possible, and that sorted the problem out.

I've looked for replacement pins on eBay and there are genuine Toyota items on there but they are all solid brass - which is what I now have, so I'll probably leave well alone if it gives me no further grief.

Very frustrating, and nearly resulted in me calling an auto electrician, I'm just glad I persevered and found the culprit!

[TonyL]

Thanks for this. I've been putting off doing mine. It will need looking at soon for the MOT - just two more to go & then it will be exempt. I'm thinking the problem may have something to do with having taken the steering wheel off to fit a spacer. I'm much more comfortable now that the steering wheel is further away from the pedals.

You don't realise how often you use the horn until you have one that doesn't work.

[John]

Agreed, one previous occasion my horn had failed I only realised it had packed up when I tried to warn a lane changer that I was right next to them! Fortunately they noticed I was there in time.

When you fitted the spacer did it just fit between the wheel and the original hub, with longer bolts? If so the original plunger and brass ring should have remained in place. Still worth checking that you've got a reliable contact, the surfaces may be dirty, the plunger spring too weak ir broken, or the wire to the back if the plunger could be loose.

Another problem I had was the horn button. I fitted a Momo wheel and the original button wouldn't fit. I had to use a Momo button, and couldn't get a decent earth connection just through contact with the hub (which is how the original works). I had to run a dedicated earth wire to the button switch. Your hub spacer may have disturbed the earth connection to the button.