My headlights decided not to come on last night, checked everything over and kept flicking the switch, the drivers side came on eventually but the passenger one wont at all.. fuses are fine and I swapped the bulbs over and the bulb that was in the passenger side now worked when in the drivers side :S my side lights and full beam work as normal in both headlights, any suggestions?

Are the GTI headlights?

Or HID's?

If so probably a faulty ballast

Sorry I forgot to mention, they're standard reflector headlights.. just did a polarity test and it seems there's no voltage going to the terminals for the spade connectors

Ok so no voltage.

Next thing to do is a continuity test from the fuse box (fuse removed) to the connector, see if there's a break in the wire, could check/clean you earth point aswell

Edit: also check the voltage to the connector of the lamp not just the spades inside the light, could be the light unit at fault itself

Edited 18 August, 201313 yr by matt01

Cheers pal will give that a try now, any idea of what could have caused this?

Snagged/trapped wire causing it to short, loads of things.

Just need to locate if its the wire at fault or the light unit and go from there

Right I've taken the headlight unit off, did a continuity test on it and everything is fine, so I then tested the plug that goes into the unit and that has about 11.80 Volts, which leaves me to think that its the spade connector plug in the unit that has a poor termination but it all looks ok.. so confused, I'm going to plug another unit in that I have lying in my garage and see if that works :)

Other unit wouldn't light up either, in the words of james may, oh cock.

Where's the earthing point? Trying to trace the cables but cant see anything

Last update before I take it to a garage. Got a good earth and voltage going to the dipped beam, nothing comes on.. plugged the whole light unit into the other side and it came on, swapped the actual switch for another one and nothing changed.. anyone have an idea what's wrong before I book it in a garage? which I really don't want to do :/

If you have 12v feed then your earth sounds shit. Can't remember if they have them just behind each light as well as on the gearbox.

May be worth splicing a bit of wire into the earth to the lights and out it to the earth of the battery, if it lights up you have a earthing issue

Earth is fine mate thats why I'm so confused, cleaned the plug and still nothing.. just going to have to avoid driving at night until friday

The earthing point is below the passengers headlight on the chassis leg.

The wiring for the lights isn't the best setup tbh and is on the basic side. The wires run directly through the switchs which means it puts a lot of strain on the components.

What you could try is running a wire from the yellow wire on the car loom plug behind the headlight and one from the brown then connect straight to the bulb. If it lights up then it's the wiring inside the light. It could be showing 12v but not have enough current to light the bulb.

Once it's sorted I would recomend using a decent relay harness as it would avoid these situations untie future and the output would be so much better.

Also, are the bulbs okay? Or is the base melted? Or are they higher wattage?

So one light unit doesn't work - but when you swap the known working one onto the side that doesn't work - you get light?

That means that the loom to both sides is working, since one light can light up on both sides.

It's your light at fault, either the bulb or wiring..

If you put the known good bulb into the "bad" unit, try it on both sides, and no light, it's your headlight..

no neither of the light units work on the passenger side, but they both work when plugged into the drivers side so there's nothing wrong with the bulb or light unit.. got to be wiring yet i'm reading nearly 12V on both sides plug there's a good earth, what dixy said makes sense about not being enough current to light the passenger side

Edited 20 August, 201313 yr by Tom3dwards