I am stumped - headlights

[geoz]

Hi,

I need to tap into the combine wisdom of the forum. I am totally stuck here (and I am starting to get very frustrated).

- the car runs very well, no issues there
- most of the electrical systems work; dash lights, running lights, radio, aircon, blowers, ...
- what does not work: brake lights, main headlights, high beams

Fuses look ok, no visible damage. I wriggled them around a bit to make sure they make good contact.
I removed the head light switch and on contact #75 I only get about 3V.

Oh and what's also odd: my windows will NOT work with the doors closed, but will work with the doors open. The window regulator relay is warm all the time so it seems it gets current when the car is turned off & the doors are closed. the interior light does go off when the doors are closed, so the door jamb switches are (probably) ok.

What is wrong? Why is there only 3V at 75?

Thanks in advance for your help.

[afterburn 549]

Look ok?
Does not count .
KISS
Check them for continuity .

[zl0ca]

Have you checked the grounds?
I was having issues with one of my tail lights for weeks and blinker and it turned out to be three things:
Relay for hazard lights gave out
A disconnected ground behind one of the front blinkers
and previous owner put the incorrect bulb in for the blinkers.

keep at it, answer will come

As far as the window goes, you might have a short with the door closed. Check the harness

[geoz]

First of all thanks to everyone for your contributions.

I have armed myself with a copy of the electric diagrams and will first follow up on why I only get 3V on pin 75 of the headlight switch. I think that is the key to the issue.

I'll work my way back from that pin. Could also be a faulty relay somewhere. I remember the issue started pretty immediately. I started the car, head lights worked fine. I checked the brake lights & got a no show so I turned the car off to replace the bulbs. Next time I started the car the headlights were gone ...

[svenhanne]

75 is according to my diagram the switched positive feed from the ignition switch (red cable with white stripe) - if you get 3V there it may back-feed through the switch and you may have ignition switch issues rather than light switch issues. 75 is the main power source for all lights - if 75 is the same in yours as mine (pelican diagram picture attached below that someone else had posted before - would give credit but can't remember who it was) then try and direct deed it some 12V and see if lights work now - and then sort out feed issue from ignition switch

please check below is same as your car first, cheers, Sven

[geoz]

Originally Posted by svenhanne

75 is according to my diagram the switched positive feed from the ignition switch (red cable with white stripe) - if you get 3V there it may back-feed through the switch and you may have ignition switch issues rather than light switch issues. 75 is the main power source for all lights - if 75 is the same in yours as mine (pelican diagram picture attached below that someone else had posted before - would give credit but can't remember who it was) then try and direct deed it some 12V and see if lights work now - and then sort out feed issue from ignition switch

please check below is same as your car first, cheers, Sven

That was on the money!
I fed 12V back to 75 from 30 and all the issues were gone (at least the ones I could easily verify: headlights were back on, the fresh air blower was back online, heater servos working again & the electric windows were working with the doors closed - interesting how much everything is realted). So ... now I need to look into where the 9V are going AWOL.

Ideas anyone?

[svenhanne]

I bet a hundred bucks that the electrical portion of your ignition switch is burned out and has contact issues, your 12V feed to the light switch comes directly from the ignition switch - cheap available from Pelican Parts, have just fitted one, its a genuine part. If that isn't at fault in your case then its between the battery and the ignition switch (fuse or connector). Good luck.

[geoz]

Originally Posted by svenhanne

I bet a hundred bucks that the electrical portion of your ignition switch is burned out and has contact issues, your 12V feed to the light switch comes directly from the ignition switch - cheap available from Pelican Parts, have just fitted one, its a genuine part. If that isn't at fault in your case then its between the battery and the ignition switch (fuse or connector). Good luck.

That sounds like a probable cause.
Ordered one right now! Thanks Sven

[1983Cabrio]

Headlights / High Beams - I have an 83 SC, and a new Turn Signal Switch (easy fix) made everything better.

[Trackrash]

I recently went through the electrical system on my car, due to light issues. There were many connections that had resistance in them. I cleaned the fuse blocks and replaced the fuses, and gained a half a volt. I cleaned the the screw connectors on the fuse block, again gaining half a volt. Same thing with the grounds.

Not saying this is your problem, but it is worth taking a sensitive volt meter to check. With the electrical system on, place the volt meter probes on either side of a connecton. If it registers a voltage, there is resistance probably due to corrosion.

BTW, if you don't have a headlight relay, now may be a good time to add one.