no headlights on 1975 280Z

[EScanlon]

Quote:

Originally Posted by EScanlon

The biggest problem with your test, is that you don't specify WHAT it is you're testing for. Add to that that you don't reference with respect to WHAT you are testing against.

I am testing to determine why my headlight is not working..

I understand that you are trying to determine why your headlights aren't working.

What you're not understanding is that your diagram with "ON" and "OFF" doesn't explain if you are using a testlight that draws power from the circuit it is testing to light up, or if you are using a continuity meter that register ON for continuity and OFF for no continuity, which normally requires a test light with it's OWN power supply independent of the circuit you are testing.

The first test light doesn't check continuity it checks for power, and power with relation to a ground or the return portion of that circuit. The second one just checks for continuity and doesn't indicate if there is or isn't power present in the circuit (although it may get affected by the presence of power in the circuit).

ON = What? Voltage 12v or continuity? Continuity with regards to what? Voltage with regards to what?

I am checking for continuity. For example, when I turn the headlight switch once, the WR (white red) wire has power when I attach the test light to it... thus, "ON".

That's not continuity that's voltage you're registering there, and voltage with respect to ground. The W/R is always Positive with respect to ground, when in the SECOND position it connects to the Red wire and power is then directed to each headlight via the fuses.

Have you checked the wiring diagram for your year?

I have been studying the wiring diagram.. but sometimes checking in with folks helps... nevertheless, I will visit it again.

There is no "magic bullet" when it comes to wiring. You have to look at the schematic time and time again simply to trace where the wires connect to each other. Others would just be doing it for you and wouldn't have your car there to check their findings.

Tracing the wires at the combination switch to their respective sources / destinations will show you that only three wires affect the headlamps. That will give you an idea as to what you should be seeing/measuring. You'll note that there are TWO fuses for the headlamps, one for each side. They BOTH receive power via the Red wire coming from the Combination Switch. Do a continuity check from the Red wire contact at the switch to the fuse box and you'll see that they do connect.

Then when you trace everything back (fuse box to headlamps and back to the combination switch) you'll see that BOTH headlamps return the ground portion back through the combination switch to the Dimmer switch...which connects to a little black wire from the Turn Signal Switch to the Headlamp / Wiper Switch.

Did you check and/or replace those fuses? (Note a VISUAL check of the fuses is worthless, these glass tube fuses often look OK, but in fact are NOT.)

I replaced all the fuses with the correct ones. I cleaned all the connectors too.

That is a good step. Too often it's a visual check that is the problem.

Have you checked to see if you have power at the headlamp connector?

There is power at the fuses for the headlights.. I tested all points of contact at the fuses for continuity.

There is no power at the headlamp connector for both headlights.

You don't specify if you have switched the Headlamp switch to it's second position, if you don't you won't have any power to check.

But presuming that you did, then check for continuity from the fuse box to each of the headlamp connectors at the front of the car. This will require alligator clips and long leads, but it will help isolate the location of the wire break.

Not trying to p*ss you off, but we can't see your car from where we're sitting, which makes it extremely hard to diagnose.

2¢

E

I hope this helps. .. and sorry for the inconvenience.

I'm trying to help you, but you need to do some of the legwork too.

Give the above a shot and see if that doesn't help.

E