I have a 94 Dodge 4x4 diesel. Im having a electrical problem with the ECM. The truck starts and runs fine for a while and then the tech, AC, Alt. and overdrive stops working. It appears as if the ECM has shut down. Codes show a voltage problem. Had batterys and Alt. checked and all shows good when operating. So far I replaced the crank sensor and that wasn't the problem. I checked to see if i was gettng power to PCM. I don't think its a wiring problem because shock and vibration has no effect.
My question; How do I to tell when the ECM is bad?