I am currently working on a 2001 GMC Sonoma, and it has something wrong in the electrical system. During the day time, obviously the Daytime Running Lights are on, however, if the headlights are turned on, all is lost... At night the headlights will not operate unless the high beams are engaged. I have read of this problem in other forums, but have yet to find a solution or an answer... If anyone can point me in the right direction, it would be greatly appreciated

thank you

check your dimmer switch...

:bump: for more input.

i've heard of cases like this, and the problem lies with the dimmer switch malfunctioning.

I personally wouldn't worry about it.........I have a 99 S10 Xtreme (same as your noma) and my DRL's stay on all the time unless I override it............and at night, the DRL's automatically go to lo-beams (there's a sensor in the passenger dash speaker grille) and the taillights automatically go on also..........great innovation I must say, and keeps ya from getting a DUI.................

Yeah the dimmer switch has a breaker inside of it because headlights are not fused. Very likely culprit but the only way to be 100 percent sure is with a DVOM and a schematic.