97 Buick Skylark- Randomly shuts down while driving

My car randomly shuts down while driving and while waiting at red lights. Everything dies, and then it starts back up after waiting for 5 minutes. My mechanic has looked at it twice, and can’t find a single thing wrong. It happened at a red light when the air conditioner was on, and it also happened while driving on the highway without the air on. Everything shuts down. We turn on the hazards and coast to the side of the road, wait 5 minutes, and then get going again. Does anyone know what could be causing the problem?

Have your mechanic replace the positive battery cable assembly.

Your vehicle is old enough where the cable on the GM side mount terminals can form corrosion, causing the vehicle to shut down.

Besides, it’s a cheap diagnostics.

Tester

The problem may be with the ignition switch. Do the warning lights come on when this happens? If not then it sounds like the switch may be the cause. Power has to pass through the switch for the warning lights to work.