Bright Lights cause truck to die

Just a wild guess but maybe you have a short of some kind in the steering column.

F_O_R. I Think your on the right track, those are technically called the passing light switch and if it's doing this only with high beams on that would be the first thing to do to

One thought though.. surprised that your not blowing a fuse

I had the GMC dealership fix it awhile ago. There were two shorts. I can't remember where exactly but it was under the hood. They used the numbers 3 and 6 to identify the location on the receipt. No problems since then. I'm actually surprised how good the 5.3l Vortec sounds because this Yukon has had a very hard life. No sounds from anything on the engine besides the exhaust manifold which has a leak but it seals itself after a few minutes of running.

On my 2004 Yukon I'm having that problem along with the low beam doesnt work on the driver side. But if i unplug high beam bulb or remove the relay the truck wont start. Also upon removing the relay the throttle body goes nuts.

Maybe a grounding problem.

Odd as it is I swapped transmissions then this problem came about. Prior to this the door locks on each sides rear door lost power as well as the back door lock. All three lost both lock and unlock function.