I thought I'd give some advice on electrical issues.

Make it a habit every fall or spring to clean your grounds, most issues in regard to shorting or weird codes can be traced to a corroded ground terminal.

1. Remove and clean all your battery terminals and clamps, leave them off till your done with the rest of the truck. If the batteries are more than two years old have them load tested.

2. remove and clean all the wires on your starter and solenoid (be careful the solenoid can be delicate) also remove and clean the ground strap from the solenoid to the starter case (a lot of folks replace a starter needlessly because of this)

3. Locate and clean all the grounds you can find along both frame rails and the cab, look closely as some mfg'rs can be sneaky in regard to ground placement

4. When you reassemble everything use nonconductive grease to protect everything.

Most important, wear safety glasses. I have more than twenty years experience as a mechanic and three years ago I grounded my batteries because I wasn't paying attention, thankfully aside from the flash nothing happened.

Good luck and be safe.