mikebar4

Had a light go out on my drivers side (dim) changed the bulb and didnt think anything of it. Noticed it was still out. Changed it again and nothing.. Checked the 20a fuse for that side and its good. swapped relays,, still nothing. Swapped bulbs from passenger to driver side and still nothing. I put a meter on the plug where the bulb goes, getting 13.6 volts...... any ideas on this one?

Bern

Check the ground at the bulb connector . Check the terminals inside the bulb connector for burn marks.

mikebar4

Couldn't find anything on the ground wire coming in to the plug. I got a test light and one side has power and the other doesn't same as passenger side. Swapped bulb again (not sure why) and the bulb is good. Is there a way I can test the ground on the plug? What if I cut the wire and ran my own ground up to the plug?

oldchevy

Use a ohm meter to check the ground before you cut any wires. Put one terminal of the meter to a known good ground and the other terminal to the ground in the bulb connector. if you get no ready then that ground is bad.

mikebar4

Ok now I'm stumped!!! It ohmed out ok. One side has power, one side ground--- bulb still doesn't light up!!! Any ideas??

mikebar4

Well,, I tried process of elimination,, got a new plug... Put the bulb in and ----- nothing. Ugh. Still no luck!!!

Bern

You may have an excessive voltage drop. With a excessive resistance the circuit may carry enough power for your volt meter to measure but not enough to power up a light bulb.


Retest for power and ground while the headlight bulb is connected. You can use a pin to probe the side of the wires


Test for 12 volts between light connector positive wire and battery ground
Test for 12 volts between light connector ground wire and battery positive

mikebar4

Ok. I checked voltage without bulb and 12 volts

Kept meter plugged into wires and put bulb in.... Voltage dropped to 0

Bern

follow both wires down to the area just behind the headlight.
The positive wire goes to the x100 connector , disconnect and inspect for a burned terminal
The ground wire is also goes to G100 stud or bolted to the body in the same area.


You can also use a test wire to add good power or ground.
With the bulb connected , connect the test wire to battery positive and the end to the bulb positive wire. If the bulb works the voltage drop is on the positive side of the circuit and the ground is ok.