bang wallop lights!

[edoh]

sometimes a rear light or a headlamp doesnt switch on - a wallop near to the light brings it on again -
i sure this aint a long term auto electrician approved solution -
any ideas what i should do for a surer repair? clean out bulb holders? are there local earths to these clusters? where?
all suggesions appreciated -

[Syncro G]

One of my mainbeam headlights does this, I suspect in that case its poor wireing (preveous owner fitted square lamps but clearly wasn't an auto electrician) so treat any non VW wireing with extreme suspision! Dirty/loose contacts is also very likely so best clean them. Broken/damaged wires is possable though if its fitted in the way VW intended this could be unlikly, worth checking. Dirty earths tend to stop things working at full power or make other things work at the same time, classic example is when you see a car with a dim taillight, then when he brakes the indictors and foglamps come on with it. Best do all of the above really, aspecally with the headlamps as they WILL be brighter afterwards.

I've also had bulbs fail in the past so the filiment still touches some times and the bulb works intermitantly making me think it wasn't at fault.

If it doesn't take much tapping in a spacific area to wake it up, at least you know the problem lies local to there.