Left headlight out?

[nathans76]

My left headlight low beam is out, high beam okay. Thought it was the lamp itself but tested okay off the car. Determined no power to the low beam. I checked the fuses but okay. Where is the headlamp ground on a 76? Not sure where to look next. Thanks!

Nate

[AriK]

Check the grounds on the star pod located on the fender. There's also a black bullet connector nearby that powers the low and hi beam. The wire colors on that connector are grey and green. Clean the connectors inside, while you're at it repeat on the passenger side, same colors and another star pod.

[aj81spider]

Not sure on your year, but ground on my 81 was a wire that attached to a screw on the head lamp bucket.

When you say no power to the low beam, does that mean you measured the voltage at the connector and found none? If that's the case it's not a bad ground, you have a break in the circuit sending power to the headlight. If it is a bad ground you will have 12 volts at the connector, but the circuit won't complete so the light won't light.

[nathans76]

Correct, no voltage at the connector, so guess it is not the ground. This has been out for some time as I never drive the car at night but want things working. I do recall working under the dash and maybe disturbed a weak wire just enough to break internally. Just assumed it ground or cremated was so many issues are.

[vandor]

Most likely the fault is corroded fuse ends. The fuse is good but the ends where it touches the holders are corroded.
The crazy thing is that sometimes the corroded connection will pass a tiny amount of current, so if one measures at the connector, the voltmeter will show good voltage, but the headlight does not work.
Another possibility is that the connection in the middle of the inner fender from the car's harness to the headlight bucket harness.

[spider2081]

The crazy thing is that sometimes the corroded connection will pass a tiny amount of current, so if one measures at the connector, the voltmeter will show good voltage, but the headlight does not work.

This is so true. That is why when using a volt meter it is best to measure voltage with the load connected. In this case the headlight connected. Also best to use the same ground that the load uses. In this case a good place to check headlight power is at the bucket 2 pin connector near the grounding pod on fender well. separate the connector just enough to probe the pin with the voltmeter probe. The ground is at the pod.
A test light often will show a corroded connection by lighting dim but that is not always the case.

I have followed a number of fuel pump problems here where the voltage was measured but pump would not run. If the test was taken between the power and ground wire for the pump the bad ground would have been found sooner. In this case measure across the fuel pump terminals with the pump connected. If no voltage is measured them move the ground to the cars metal. If still no voltage the power is missing. If when voltmeter is connected to ground you have voltage the ground is missing.