I just replaced my passenger side headlight motor with one from a junkyard. I thought that a new motor would solve my problem but it didn't. It doesn't even make a noise when I turn the lights on, just like my old one. I assumed that it isn't the motor so I went to check the relay for the motor. I put my voltmeter into a socket that was supposed to give me 12 V. It read about 10.5 V instead. I checked the voltage in a socket that was supposed to be 0 V but it read .4 V. My multimeter isn't a very expensive one or anything, but I tested it on several newer flashlight batteries and it seems to be really acurate, so I doubt the multimeter is the problem. After class tomorrow I'll probably check the voltages out in the relay for the other headlight motor to compare them. I understand that the voltages can be a little off but almost 1.5 V is a little too far off, isn't it? I wouldn't normally be to worried about the .4 V difference, but that wire wasn't supposed to have any voltage across it at all.

 

try it with the engine on, i bet the headlights were draging the battery voltage down should get between 12.5 and 13.8

 

Sounds like a grounded wire to the headlamp motor. Tracing wires is always a PITA, but most likely that's where your problem is. A wiring schematic is always helpful.