95 GMC Jimmy 4x4
Tonight while driving home I went to use the high-beam and the power went out. I was traveling 55mph. The lights, radio, motor; everything was dead. The road was not lit with street lamps so I had to slow. When I hit the brakes, everything came back to life. This is the first time I've experienced this. Any ideas?

 

Sounds like the high beams maxed out alternator output or possibly a short in the headlight circuit that maxed out alternator output, causing a drop in system voltage. It's weird that it all came back after pressing on the brakes...

Can you reproduce the problem?

 

I'll try to recreate on the weekend.

Why would it restore power when I stepped on the brake pedal?

 

Did the engine actually stall out?

As far as what would make it all come back after pressing the brake pedal... That's a mystery... I can't recall seeing symptoms like that before.

 

Any chance there's an aftermarket security system installed, or a remote starter?

 

I would first check the status of your battery cables.

 

I was driving home again tonight and against better judgment I hit the high beams again. Same thing happens. The engine died and all power was lost. I hit the brake pedal and everything came back on. I hit the high beams a second time and everything stayed on. I turned the high beams on and off several times and everything stayed on. I was driving for about 5 miles both nights before turning on the high beams.