VW Polo bizarre lighting problem

Lopéz · 8 Nov 2007 at 18:55

Nextdoors Polo (P plate - Mk4) has developed a weird lighting fault last night.

It will switch on the sidelights, but not dipped or main beam.

If you indicate whilst the lights are off it's fine, but the main beam indicator lamp comes on faintly on the dash

If you put the hazards on the main beam indicator lamp also comes on.

If you indicate with the sidelights on you get alternate flashing of sidelights and indicators.

I've tried unplugging the headlight switch/hazard switch/indicator stalk in an attempt to do a quick fault find but no joy. Every combination gives seemingly random faults.

One thing I've noticed is that the Hazard Switch seems to play a big part in the lighting - it has 8 or so connections at the back - so I've asked her son who works at a scrappy to borrow a few spare switches from work.

Any VW perverts know of any "known issues" with these things?

randal · 8 Nov 2007 at 19:01

What happens if you take the fuse out of the indicator circuit and try the lights and vice versa?

Sounds like crossed wires somewhere, probably under the cowel near the steering column as they may have worn away over time - my corrado did something similar, then someone wrote it off for me so I didn't have to fix it.

I highly recommend Gloucester, near KFC. Dozy woman in a Honda Jazz, can't miss her lol.

paradigm · 8 Nov 2007 at 19:02

I'd hazard a guess at a dodgy earth somewhere.

kkelly · 8 Nov 2007 at 19:07

This happened to my mazda about 2 yrs ago water got onto the wiring behind the bash somewhere and was causing it to short cut

randal · 8 Nov 2007 at 19:13

paradigm said:
I'd hazard a guess at a dodgy earth somewhere.

*groan*

Pun-a-rific...

paradigm · 8 Nov 2007 at 19:22

Lol, I didn't intend for a pun at all!

Dogbreath · 8 Nov 2007 at 20:09

Classic symptoms of a duff earth, the indicators ground is a high resistance, so the current is taking a return path through the the headlamp bulb on it's way to earth, hence the faintly lighting main beam light on the dash. It will almost certainly be an earthing point under the bonnet somewhere.

Lopéz · 10 Nov 2007 at 16:50

Problem found - working in daylight helps

Up close you can see that the electric fan has been wearing its way through the loom bit by bit. Nice.

Problem solved. Bit of cutting and shutting on the loom and a lot of cable ties to stop it happening again.

loltim · 10 Nov 2007 at 18:01

Nice one

You owed a few beers then?

Lopéz · 10 Nov 2007 at 19:22

Yeah, but I'm in no rush to cash my favours in - it pays to get on well with nextdoor, particularly as they own our shared drive and parking arrangements could easily become hostile if we didn't all get along!