"From the diagram they have it looks like the center pin for the headlight connectors should be hot whenever the relay is activated. For some reason isuzu switches the ground side of things. The relay should be activated anytime the light switch is on for headlights (not in parking light position) regardless of high or low beam setting.
I think the problem is with the dimmer switch part. Both high and low beams are switched through it, its really the only common point that I can see to cause the problem.
If you need a copy of the diagram PM me with your email addy and I can send it to you."__________________
Thanks for the research Gizmo! Check this out, My girlfriend was in the car turning the dimmer switch when I fired it up and accidently hit the "turn signal-hi beam toggle" on the stearing column. When the turn signal was on left turn I pulled it for brights and the head lights came on and stayed on the "on" "off" buttons worked. I wiggled, jiggled and flashed hi-beams some more and the headlights went off and stayed off. About a month ago I was going to get gas and noticed the headlights were not working and hit the brights (turn signal Hi-Beam) and the headlights came on!
Last night I pulled the instrument pannel, and the button switch assembly and found the center pin to be hot, when I jumped to the 1st or second pin from the top I heard the relay click but still no headlights.
If in fact it the "turn signal hi beam switch" is the culprit will I have to pull the steering wheel and airbag to replace it? Or do you think it is the dimmer switch?
Thanks for al your help.
Michael