Used to fix a ton of Dakota's with a no-start....90% of the time it was a red/white wire going to the PCM which had corroded at a splice in the harness. This was a B+ battery power to the PCM. ASD's etc will NOT turn on without the PCM powering up....
The splices are usually along the left inner fender area...on a Full-size it could be along the firewall...time to start stripping the harness....