Depending on what happened (if anything) to the pCM, it may not communicate with a scan tool (and if you get one make sure it works on the Ford Diesels!). I had the PCM go bad on my 94 and the only thing it wouldn't do was power up the IPR (it would communicate with my scan tool, run KOEO tests, etc.). Do you have a chip installed? If so, remove it and see if that solves it. I don't have the PCM connector pinout handy, but if you can find it, you may want to check for power out to the PCM connector pins. Assuming your truck is not a California truck with splitshot injectors (PCMs are hard to get for these), you could try someplace like RockAuto for a PCM (I picked one up from them for $115 plus refundable core). Cheers!