VW Golf Mk2 Headlamp problem!

I take it to measure the 12V you took the connector off the bulb?

Try it with the bulb connected. If you have a poor connection or a burnt-out switch contact that is resistive, that 12v will drop an awful lot on-load.

If you are getting power to the connector, then I'd check continuity on the earth.

If the 12V isn't across the headlight bulb when it's meant to be on, it must be across somewhere else - that's where the bad connection is.

I had a frustrating problem with my old Polo recently - no dipped beam after driving for a while, but dim-dip worked when sidelights selected with ignition on. One of the connectors had come adrift below the fuse-box. Could be there's a loose connection somewhere for you. Do the simple things first before looking into inaccessible places!

You need to test the voltage with the bulb in the circuit... Any other test is useless.

Thanks for the quick response everyone. I have tested earth continuity on both negative pins and that is fine. I have just measured the voltage with bulb in connector, and I have 0v when the switch is on. Does this mean I just need to replace the connector or could the problem be elsewhere you think? If so, is there a way I can trace it?

Thanks,

Craig

My money would be on the switch, or if your car has the stupis dim-dip system, the dim-dip relay. Check the connector anyway, and the fuses and fusebox for dirt or corrosion.

Funny you should say that as I just pulled the fuse out (didn't bother checking it before seeing as I had 12v to the switch) and it is quite corroded. Swapped it with the other headlight fuse and it works! Weird thing is, swapping them round makes them both work?? I'm gonna pick up a couple of new ones anyway.

Really appreciate the advice here so thanks.

You've just knocked off the corrosion I expect. Cheapest repair around - apart from replugging the connectors in properly!

Could be the connector, fuse/circuit breaker, wire, or other connector(s) in the circuit. You'll have to back probe down the line until you find the fault.

Having a *good* (say a Bentley or factory) diagram will be worth its weight in gold!

You got lucky!

Probably a bad connecton at the fuse (common in VWs in the past). Did you see any corrosion on the fuse pins when it came out?

And the next job to do is to use the current feeds to the lamps to switch a pair of relays supplying 12v to the bulbs direct from the battery. It's probably the quickest and easiest way to upgrade the usual shonky VW headlamp wiring.

That was a very popular mod a few years ago. Affected the MK1 worse though. Someone (BR Motorsport?) used to make a kit with relays and a loom that just plugged in. It made quite a difference, as there's quite a voltage drop across the cables and switch.

I thought that myself! Could have been a much bigger pain in the backside I reckon.

No, couldn't spot any corrosion there but it's prob worth a closer inspection to be honest. Won't do any harm to check the other fuses I suppose as there must have been a reason for this happening...

Cheers,

Craig