96 blazer ls 4dr 4x4.If i put the truck under heavy electrical draw, Ac on, radio on. wipers on and headlights on. It will suddenly go dark, engine shuts down, dash shuts down no power anywhere. If you wait 20-30 seconds you hear a click and all is well again. You hit the key and it refires. The radio and clock both lose time and presets. I was a collision tech for 20 years and i know how to look through an EVDM but this has me stumped. i can find no "master" circuit breaker that has control over all of the different systems. The only thing i can think of is the ignition switch/harness. We need to put a trans in it but if i can't get the electrical gremlins fixed that will be a waste of time. I hope the collective brain power of the forum members can point me in the right direction. Thanks for your advice

 

check your battery terminals, i had a similar issue where you'd hear a pop sound and everything would cut off occasionally if you turned the key to start, tightening the negative terminal fixed it though to be safe i'd take off ground and positive then put them back in in reverse order and make sure you get them snug, its a sidepost battery so dont bolt them down too far.