I recently acquired this 1989 caprice classic with only 85k original miles. Garage kept and 1 owner it's whole life. Great shape and runs good, or it did run good until today.

Today I started it and after idling about 5 minutes it just died. There is no electrical power to anything now. I checked the 30a circuit breaker on the fuse block with my ohm meter and it is OK. I don't know the location of any other large breakers or fuses. Any ideas on what else to check or where other main fuses/breakers are located? TIA

 

I suspect a broken or very corroded negative battery cable.

But, let me ask: does the horn work? Do the headlights work?

If absolutely nothing works, then I still say the ground cable from the battery. If the horn and lights work, it could be a "fusible link".