I have a Nissan 70 forklift. It had some engine work done but then wouldn’t go into gear. They replaced the wiring harness, ignition switch, and a few other items but then gave up before it would move again. After having it towed to my shop I check the parking brake switch and found it to be bad. I jumped that, but still joy joy. I checked the brake switch and it seems to be switch on all the time, so I disconnected one leg, still no change, there is seatbelt switch wiring, but no switch. I jumped the terminals on the connector and a buzzer comes on, so I disconnected the jumper. The engine starts fine in neutral and won’t start in gear. I then disconnected the wire connector at the transmission solenoid, it is a four wire connector. I can apply 12 volts pos and neg to two of the terminals and get forward and reverse on the other two, so the trans is functioning fine, it just gets no signal to go into gear. I pulled the cover off of the transmission module in the right side footwell it has a blinking red light with the key on, other than that it is a mess of wires that I don’t know where they go. I located the transmission switching module next to the ECM, nothing obviously wrong with it. Has anyone a wiring diagram? Is there some sort of transmission troubleshooting chart, or a shop manual? Also, I am having a little trouble figuring out the exact model, as the name plate is scarred in that section. I have the serial number. Any help is appreciated,
After a little more investigating, the TCM is not getting any signal from the transmission shift control module, and that is not getting any signal from (?) the ECM? Not really sure where it’s signals come from. I did check the shifter switch, brake switch, and replaced the parking brake switch, still nothing. I am leaning toward a bad ECM (PCM?), but not really sure how to troubleshoot?