Lights Not Working

[eastcoastz]

Hello.  I have a 1971 240z... I just replaced the headlight/combo switch because the old one was cracked/not working (which is how it was when I got the car).

 

Now the headlights are working, but the tailights, dash lights, and license plates lights, etc (everything that should come on when the headlights come on), do not work.

I'm not seeing any blown fuses... is there any way to tell if this is an issue with the headlight/combo switch that I just put on?  anything else to check?

 

Thanks in advance!

[SteveJ]

Yes, you can test.

1. Remove the steering wheel cover.
2. Unplug the 6 pin connector.
3. Turn the switch from OFF to position 1 (no headlights).
4. Check for continuity between the green/white and green/blue wires on the switch. (See photo.)

Also, in the fuse box, measure voltage TO GROUND on either side of the 3rd fuse down on the right. Both sides of the fuse should have around 12VDC to ground. The 240Z fuse box is notorious for damage to this area of the fuse box.

So, what can cause the parking lights not to come on? Here are some causes:

1. The fuse is bad or improperly seated.
2. The 6 pin connector on the switch was not plugged into the dash harness or was not plugged in correctly.
3. One of the solder joints on the switch has gone bad.
4. The mechanism in the switch is worn out so it is not pushing the rocker to make contact in the switch.

If you cannot diagnose this yourself, you may need to send the switch to someone like myself who has the experience to diagnose and repair headlight switches.

[eastcoastz]

Thank you @SteveJ  I will give these things a try over the next couple of days and write back.

How much do you charge to rebuild/repair headlight switches?

 

Another odd (electrical) issue if you have ideas... the inner top brake lights (top right on drivers side and top left on passenger side) are not working.  All other brake lights work just fine.  When I hold a multi-meter to the two contacts in the bulb socket, I can voltage on one contact but no voltage on the other (on the drivers side)... on the passenger side socket, I get voltage in both contacts, but not as high as one of the other working sockets that I tested.

I would have thought that since I'm getting at least some voltage on both contacts in the passenger side socket, that the bulb would at least light up dimly, but it doesn't.

Any ideas?

[eastcoastz]

Here's the latest update after testing the items that you ( @SteveJ ) mentioned:

 

I tested for continuity between the two wires you mentioned.  There was no continuity... is there supposed to be? 

 

I tested for continuity between those two wires on my old (cracked) switch and there was continuity, so I tried putting that one back on, but I still just got headlights and no running lights.  Then I took off the old (cracked) one again, tested for continuity again and now there is no continuity.  Very odd that there was continuity before I installed it and then no continuity afterwards.  What's going on here?

 

I tested both sides of the fuse and got 12.15 volts... one side was fluctuating a little bit, but I don't think it was enough to make a difference.  Attached is a picture of the underside of the fuse box (right under that 3rd fuse down)...  looks pretty clean to me.

 

Where do you suggest I go from here?  I'm at a loss as to why none of the running/dash lights are working.  Thanks so much!

[SteveJ]

There is supposed to be continuity between those wires when the parking light switch is in the ON position.

[eastcoastz]

@SteveJ - oh shoot... that's the step I forgot, I'm sorry! 😞  I forgot to move the switch to the parking light setting when disconnected.

 

I read in another thread that I could try a jumper/wire between the white/red and green/white wires on the switch to see if the running/dash lights come on.  Is this something that I should test out? 

 

If the lights come on with this test, what does this tell me?

Edited September 9, 2021 by eastcoastz

[SteveJ]

I don't like doing tests with loose wires. It's too easy to short something out. I prefer taking measurements. For instance, with the 6 pin connector plugged in, you should have 12 VDC to ground at the green/blue wire.

[eastcoastz]

Thank you @SteveJ  I'll check that measurement.

How much do you charge to rebuild/repair a combo switch?