My 91.5 had an electrical surge go throught the truck when the voltage regulator went out and blew all kinds of fuses . Sense then my speedo/odometer stopped working , brake light wont go off and the grid heaters stopped working . Could this be a problem caused by the pcm ? I replaced the speed sensor and switched the guages with no luck

 

It could be the PCM, but I would check the fusible links first, located drivers side of the engine compartment right below the hood hinge..

 

If it's not charging along with those others symptoms id say pcm my spedo quit also AC and it quit charging i replaced pcm after hours of agonizing wiring chasing i simply just gave the pcm a love tap and it would work went to dealer it was like 350 problem free for over a year