Oil Light and Generator Light Issue

[Whistler]

Hi all,

We finally have the engine back in and it seems to be spot on. However we cannot work out why the Oil Light and Generator Light don't come on on ignition. I have replaced the entire loom and up until yesterday all the lights, indicators, horn etc worked perfect. The only thing we have added is one of Chris' rev counters (which is awesome by the way!) and I had to add a late bay ignition switch as I seem to have a late bay ignition barrel. We still only used the 3 wires on the switch and the rev counter works.

The oil light switch has the blue/green wire to the dash and the generator (I believe is an alternator with an external regulator) is wired up correctly (as far as we can tell).

It seems that the oil light switch is ok when fed a live but then the indicators don't work (the bulbs, and I think the fuse blows). When both wires from the engine are fed a live the bulbs light up, so the bulb and the wires are OK. So there must be something at the engine end, or something we have done at the dash pod?

Any one have any ideas? We presume it is something silly/easy to fix?

Ta!

 

[KateLovesPurple]

Sounds like you have wired up things incorrectly. Both the warning lamps are fed 12v at the dashboard and grounded in the engine bay, not the other way round. Could be you have this already, could be I misunderstand what you describe.

 

[Foz]

Have you used original bulbs or replacement LED bulbs? When i installed LED into my Alternator lamp it messed it up ie. it wouldnt go off. Giving the false reading it wasnt charging. Replaced it back with the original bulb and now works fine. If using LED it may be affecting it in some way? Just a thought from my experience.

Own a Bay?.........Feel the Love!

 

[Whistler]

Cheers guys. I'll have another look at the wiring tonight. I get it's a switched earth so maybe it's wrong at the engine? The lights, indicators all work ok.

I'm using normal bulbs, not sure if I replaced those particular ones though.

 

[newhippy]

Is this of any help to you?
http://www.vw-resource.com/speedo.html#diagram" onclick="window.open(this.href);return false;

 

[KateLovesPurple]

Have you used original bulbs or replacement LED bulbs? When i installed LED into my Alternator lamp it messed it up ie. it wouldnt go off. Giving the false reading it wasnt charging. Replaced it back with the original bulb and now works fine. If using LED it may be affecting it in some way? Just a thought from my experience.

Own a Bay?.........Feel the Love!

All LED's on mine, working absolutely fine. They weren't bought LED replacements though, they were just LED's to which I soldered an appropriate resistor and fitted in the original sockets. Again, bearing in mind the polarity of the LED's.

 

[Whistler]

So with the fact it's a switched earth the oil late comes and goes when you start the vehicle but the generator light stays on. However, now they work(?) The indicator lights don't work.

I think it might be time to get an auto-electrician in

Any one know a decent one in Croydon, Surrey?

 

[matt-me]

Try asking speedy jim on VZI, he's a great help with all things electric

 

[Paul Weeding]

You've got Pete Nice round that way... He does mobile VW work

 

[Whistler]

Thanks Matt and Paul, I've given Pete a call so just waiting for a call back.

I did some more looking tonight and when you unplug the bulb holders and earth it they flash. My understanding is that they should be earthed in that scenario, so it's almost as though the flasher unit is sending a live up the blue/red cable to the bulbs.