engien wont shut off

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.

I would guess to bet the rotted out cab harness is bad.. I would unplug all the connectors and make sure they are all clean and good looking.. could also be a bad ignition switch... not sure why if they are both same year and engine that any of the plugs would be diff.. it should of been a straight swap over.. if u check the wires and they are clean/good.. and the switch is good.. u might want to use the hacked up one if it was in the original running truck..

im doing electrical right now on my swapped truck.. been messing with it a few months now and its still not even in the truck yet LOL... so take ur time and check everything... if you have a multi meter that tests continuity use it to see if each wire is making a connection..


Steve

The harness is good, the problem is the plug in the back of the cluster, and the engine not shutting off. there are two 3 prong plugs that go into the back and i don't want to plug the wrong one in and accidentally damage something. The key switches between accessory, on, off, and start. I know the harness is good cause the truck it was in ran perfect and the gauges worked. In my haste to get the swap done I forgot to label the 2 individual plugs.

The wiring diagram is less than helpful

https://imgur.com/q0yrXPL

that links to a picture posed by another user. My cluster is more like the one on the bottom, it just doesn't have the little black switch with the wires coming off it and mine says Canada instead of usa