Headlight Master Switch Melted

I recently replaced the light master switch as the origional one had disintegrated (with age I think), I purchased a replacement switch and installed that, all lights appear to be working well although I hadnt done any real night driving until yesterday.

After about 25 minutes of driving I suddenly lost all lights, this was slightly disconcerting as I was passing parked cars on a narrow road! A quick thump of the dash and the lights came back on. Pulling up where I could I found that the switch itself now didnt have any spring to it and I couldnt turn the lights off.

On examination I found the back of the switch to be smoldering and was too hot to handle, so a quick bodge to get me home the last mile or so and I was left to ponder all that advice I had read before intalling Halogen lights to replace the original units and how you should use a relay!

My question is, should I try an source that can handle the added watts from the Halogen lights or do the harder task and put a relay into the circuit?

My calculations are as follows 2x55w Halogen + 2x5w sidelights + 2x5w rear lights = 130watts therefore 10.8 amps potential draw, adding 25% for safety I would need a switch that can handle 14amps.

I'dve thought the original switch would have handled 10 amps, check for a short.

Use a couple of relays. That way you'll at least be able to fuse the headlights. I'd be tempted to replace the wiring from the relay to the headlights, too - not too hard a job with the relays in the engine bay.

:5biagree::nothingtoadd:

\i fitted two switches from paddocks and they both lasted about an hour.
I then fitted a genuine switch and four years later it is still working fine.

was it a cheap switch ...i had one from cradocks and my kids played with it and it took aprox 5 flicks on and off for it to be fooked ....had to buy a gen one for a **** load more ...

oxides said:

Use a couple of relays. That way you'll at least be able to fuse the headlights. I'd be tempted to replace the wiring from the relay to the headlights, too - not too hard a job with the relays in the engine bay.

Click to expand...

Good call


Relays are your best option, maybe not original and can be expensive, but imo it's a well worth upgrade. Also if it does blow the relay it's much easier to join the 2 wires in the engine bay, than all that mass of wires behind the dash

Well I guess the switch was on the cheap side, it was under £6 +postage (from DLS on ebay). I think using a relay will be the best option just so that I'm sure of what's likely to happen and as moley says, at least you can get to the wires under the bonnet (I have a second fuse box under the bonnet so it shouldn't be so difficult)

Look @ vehicle wiring products . Most of their stuff is fairly cheap and i've had no problems with their quality.

VWP - Relays menu

There's a sticky in the common faults and queries section about wiring relays thats good if you're not sure about them.

relays (fused type )would be the best way to go. Wire the coil positive direct to coil and negative side of coil controlled through switch virtually no load through switch

Relays installed last weekend, and very happy to accomplished the job as I'm far from being a mechanic/electrician. With some reading and taking your time over the job then these things CAN be achieved.

Thank you to everyone who contributed with answers and suggestions.

This weekend will feature the installation of 20amp 'cigarette' sockets in both the dash and the rear tub.