Spitfire 1500 Horn relay...

Should be on the bulkhead near the battery In article , Jon Tilson writes

"Jon Tilson" realised it was Mon, 3 Nov

Is the commission number on your car higher or lower than FH100020? If it's from 1978, it should be higher. According to the diagrams in the BL workshop manual, later 1500's didn't have horn relays.

That could explain why I cant find it. Its the later type with the mini/marina/allegro column switches. Is that the later type? But then I cant think why else the horn is behaving the way it is... Jon

Are there volts both in and out of the push when you push it with the horn connected? Disconnecting the push and measuring the output with a meter on no load isn't a reliable test, as the meter has far too high an input resistance. If it's difficult to probe the connector without unplugging it, use a test lamp (6 watts or so) instead of the meter.

My money would be on dirty /burnt push contacts. Most of this generation of Lucas stuff can be opened up and the contacts cleaned - or a squirt of contact cleaner might just work.

instead of the meter.

Yes indeed but there more -- On the small Triumphs (ad Lotus, TVR and other 60s british kits) with a centre push horn, the horn switch earth through a carbon brush on the steeing rack pinnion cap, caused lots of trouble on Lotuses, the two main points of faulure the carbon brush itself and the little earth wire that connected both halfs of the steering column coupling.

Never having worked on the electrics of a late 1500, I have to ask if the steering column acts as the ground return, as it does on the earlier cars with the horn button in the centre of the wheel. If so, you're probably lacking the link wire across the lower column coupling. Fitting a heavy duty coupling with a UJ instead of the rubber disc eliminates the need for a ground wire. It will aslo last considerably longer, Cheers, Bill.

-- Rarebits4classics .......just what you've been looking for

PO Box 1232 Calne Wiltshire SN11 8WA United Kingdom

"Jon Tilson" realised it was Mon, 3 Nov

That's the one. More commonly (and more status-friendly) known as TR7-type switchgear.

If you have voltage at the horn when the button is pressed then surely you have a bad earth??

But I'd expect all these to have a relay. It was only with the introduction of a stalk type horn 'push' they dispensed with them on some cars.

In article , Dave Plowman writes

Triumph were a bit odd there - Spitfires and GT6s had a relay when they used the centre push. But Heralds and Vitesses, fitted with identical steering wheels, did not.

Also the "carbon brush" was not a carbon brush. It's a plastic tube with two brass slugs, spring loaded and connected by a small wire internally. I have had that wire break on one car, and was able to repair it by soldering in a new piece of wire.

In article , William Davies writes

I don't think so. Certainly on the saloons (dolomite, 2000) this type of horn stalk is wired on the +ve side, and the horn itself is earthed.

In article , Frank Butcher writes

If the voltage is only there when the horn isn't earthed (like the poster said) then no, it's not a bad earth problem, it's a high impedance somewhere in the circuit. Look for dirty contacts, either in the switch or in any loom connectors in the path.

None of the small Triumphs up to the early 1970s had a horn relay, I can't comment on the later ones without referring to manuals, Cheers, Bill.

-- Rarebits4classics .......just what you've been looking for

PO Box 1232 Calne Wiltshire SN11 8WA United Kingdom

Thanks guys for all the suggestions. As to the centre horn push AFAIK this doesnt apply to mine with the horn switch on the column stalk. It ended up being a dirty contact on one side of the fuse. Couldnt understand why the indcators worked but the horn didnt...that was why.

Jonners