02 Chevy 3500 quits while driving, all electrical shuts off. This is my work van, I am a Honda mechanic and can’t figure it out. I need my truck for work on Monday! Think it might be ignition switch??
I think it might be a bad battery ground.
If it is the ignition switch, usually wiggling the key when this happens restores the electricals. Try it next time.
Otherwise, I’d check the ground straps on the battery-to-engine and the engine-to-chassis.
I will post just one place to check. GM has been leaving the big nut holding the big cable to the starter solenoid loose for many years, get down to the starter and check yours out. No chance you are suffering the effects from a previously leaking postive battery terminal,have a look(OK I know that was two).