replacing horn switch with push putton

[Alan L]

My 1990 car has a toggle type switch to activate the horn. When I do not want to I catch it and when I do need it confuse it with the headlight flasher . So I would like to replace it with simple push button.

 

I asked Caterham about a button and they said yes sir that would be £14, which I though was a bit steep for a button. I was hoping I could get something suitable from Maplin/etc for at a more reasonable cost. Anyone know what I sort of rated switch I should ask for? Car is fitted with air horns.

[Chelspeed]

Is there a relay? Probably is with air horns.

 

If there is then the switch only needs to trigger the relay so a fraction of an amp will do.

 

If there's no relay then you could get a switch big enough to run the air horn compressor, I guess 10A or so, but probably best to fit a relay and go with a smaller rating switch as above.

[I.Mupferit]

I have a horn push button you could have for the price of postage and a small donation to NTL if that is any good to you.

 

Brent

 

[Joe 90]

I'm afraid that's realistic for a suitably rated quality switch. You can find cheaper switches at Maplin but they wont last ☹️

 

Upgradeitis ward, awaiting open wallet surgery. 100,016 miles

[Bilbo]

Well my one from Maplins VERY small red one is fine.

 

How often does it get used anyway. 🤔

 

In my case one MOT to the next and an odd rare occasion.

 

'Can you hear me running' ......... OH YES and its music to my ears 😬 😬 😬

1988 200 bhp, 146 ft lbs, 1700cc Cosworth BD? on Weber's with Brooklands and Clamshell wings, Freestyle Motorsport suspension.

[Chris W]

But at GBP14, (I'm on a keyboard abroad at the moment and there is no "pound" sign!) it would be cheaper, and a better engineering solution, to buy a relay and low power switch. You can get a 30A automotive relay from Maplin for a couple of quid and the same for a low power switch which only has to handle less than 100mA to operate the relay.

 

The reason that cars use a relay for the horn is not actually because it's such a high power device. It only draws a few amps for maybe the second or so on the rare times you use it. The reason for using a relay is that the horn contains a large coil which acts as an electromagnet. When the horn is switched off the energy still stored in the horn coil causes a very high voltage to appear momentarily across the switch contacts and they would soon get burned away. The tougher relay contacts will cope far better than the switch contacts. Without a relay, there would also be a very large spike put directly on the main power line.

 

The thing about the Caterham switch is that it doesn't operate the horn directly anyway in a standard installation. Caterham use a relay, so I doubt they spec a high current, high quality switch.

 

Chris

 

1.8K SV 140hp see it here

 

Edited by - Chris W on 16 May 2003 23:56:07

[Bilbo]

Hi Chris

 

Well my 1988 car has a relay

 

'Can you hear me running' ......... OH YES and its music to my ears 😬 😬 😬

1988 200 bhp, 146 ft lbs, 1700cc Cosworth BD? on Weber's with Brooklands and Clamshell wings, Freestyle Motorsport suspension.

 

Edited by - bilbo on 16 May 2003 20:30:23

[Chris W]

Exactly Bill.... that's why you can use that small red switch with complete confidence.

 

Chris

 

1.8K SV 140hp see it here

[Bilbo]

Hi Chris

 

I had intended to say that but I am trying to do 2 things at the same time. (route map for Curborough for tomorrow I always get after M6 plus Oily Rag, my navigators, not going).

 

The fact that others were implying no relay me.

 

'Can you hear me running' ......... OH YES and its music to my ears 😬 😬 😬

1988 200 bhp, 146 ft lbs, 1700cc Cosworth BD? on Weber's with Brooklands and Clamshell wings, Freestyle Motorsport suspension.

[SLR No.77]

I've just bought a big black starter button for the horn, to match my big red starter button on the opposite side of the wheel. Available from RS, but still around £9. Definately a quality item though

 

Stu.