The most likely cause would be the headlight switch. All of the light circuits pass through this switch. Normally, fuses will not cause intermittent problems, but there still remains the possibility of a corroded or loose connection at the fuse, so check that as well. Next possibility is harness connectors along the way.
I recommend that you start at the switch. Check for power at the brown wire with the switch plugged in and turned on. If there is power there, then check for power at the tan wire with a white stripe. If you have no power there, then the problem is with the fuse (should be #4) or the wire leading from the fuse box to the switch. If there is power at the T/W wire and NOT at the brown wire, then the switch is the problem. If you have power at both wires, then the problem is with the wiring harness.
Unfortunately, the only way to find a problem in the harness is to trace it back to each connector until you find the break.
Hope this is of some help.
Mar 13, 2009 at 4:12 PM
