1988 f350, 7.5 gas engine, it's comes off the harness that goes to starter solenoid and passenger side headlights, beside the passenger side of the radiator, I bought the truck and it's got a few electrical issues, someone cut it just after the plug, and I'd like to wire it back up the way it goes. Thanks.

 

Both of those wires ground to the battery. They should have ring terminals on them and connect to the negative battery lead. If I recall correctly, they both serve as grounds for the ECU.