Switch Confusion

[James Cornell 10]

Here is a strange one for you...on the dash of my 205 gti all of the push buttons illuminate when the headlights are on and when you press the buttons they light up more, however the heated rear window will only work if you have the heated window and the fog light on together. The dog light and hazards work independently but the heated window will not work unless the fogs are on too. Also this applies whether the light are on or not, weird!

 

Has anyone had this issue or had the same issue?

[ginger205 1]

I don't know the answer but I can tell you French cars have the worst earths known to man! Wouldn't surprise me if this is simple a bad earth, where to start thought is another matter, get your multi meter and a large bottle of patience at the ready!!

[TheReaperWaits 6 1 Cars]

Could even be bad switches. Had my hazard switch cause problems with the others (and my indicators). After I swapped it for a known good switch all was well. The earth for the lights (main, driving, indicators etc) are situated near the headlights (from what I recall one on each side).

[James Cornell 10]

Da-da-da-da gunson 3000 to the rescue (again). I will check the earth for the light and try some contact cleaner in the switch.

 

Do the switches simply pull out with a bit of gentle persuasion or is there a special (how not to crack your dash and ruin your switches) method?

[Anthony 1,003]

Remove the trim piece that surrounds the switches (two screws underneath, one in the ashtray and one behind the clock surround) and then the switches will pop out with a little gentle persuasion.

[James Cornell 10]

Cheers Anthony I will have a go this evening

[Stu 18]

Arent they supposed to light up (dimly) with the lights on? Then brighter when hit the switch?

 

The heater switch thing is weird, id probably look for loose connections in the plugs first and foremost.

[James Cornell 10]

That's correct and they do exactly that stu, however even though the heated rear window switch is dimly lit with the headlights on and brightly lit when the button is depressed the heated rear window does not clear unless the fog light is also on.

 

Maybe I will have a chance to take them out tomorrow :-)

[jackherer 543]

It definitely has the signs of a bad earth, the rear earth is behind the left rear tail light accessed from inside the boot.

[James Cornell 10]

I have already checked that earth and cleaned it up so it is all leading to the switch now...

[Stu 18]

Or you've got the switches back to front....

Edited February 4, 2014 by Stu

[James Cornell 10]

No because the fog works on its own, although that would be funny :-)

[Stu 18]

Independently? I wouldn't rule it out, it could equally be one of the relays too, if someone somewhere has played around with the relay's and location you could still get the fog working potentially...

[James Cornell 10]

True, I think I just need to take them all out and bridge the positive and negative with some wire to see what comes on...what I really need is a dry night to do it :-)

[James Cornell 10]

Just checked them tonight and they are backwards lol. I will take out the switches and change over the connectors...job done, although I feel like a bit if a prat!

[Stu 18]

Whoop! What do i win?!

 

Glad its sorted though, quite often the oddest things turn out to have the simplest of fixes...

[James Cornell 10]

I think the lession to learn is to never over analyse a situation and complete the basic tests first before breaking out the multi-meter and stripping half of the loom out...You would have thought after 10 years of rebuilding my cars/bikes I would know better