I did a cab swap on 2 1st gen mighty max pickups. One with a good frame, rotten cab and good running gear, the other with a good cab, bad frame and running gear. Same engine and same year for both trucks.
I kept the harness from the rotten cab because the good cab harness was hacked up.

Anyway, I put it all back together and when i start the truck it runs and idles fine, but it wont shut off.

I haven't gotten all of the electrical plugged back in on the gauge cluster yet, got to sort the 2 different three prong plugs out. Would not having the battery light connected cause the alternator to back feed voltage to the ignition?

A bit long winded, but I appreciate anyone who looks.