A/C, clock, pwr windows electrical problems

On the road the A/C, clock, power windows, radio on my '91 Toyota Previa will suddenly become inoperable. The A/C fan stops and when one tries to lower the windows to cool off they don’t work either. Hitting a bump in the road or crossing a railroad track sometimes causes electrical power to come back on. The vehicle continues to run normally. Sometimes on initial startup none of the mentioned items work. Definately a hit and miss situation. I thinking it may be a failing relay, loose wire, or short… any educated ideas out there???

There’s a loose electrical connection somewhere. You’re going to need a wiring diagram to figure out why all of these things are affected simultaneously. I’m thinking a fuse box or electrical junction under the hood.

It could be on the positive side of the circuit or on the ground (negative) side. A bad ground connection could do this.

It’s not a short. A short would blow a fuse, or more than one fuse.

Thanks for your post, mcparadise. I have a wiring diagram… so I guess I better get busy.