I have been experiencing voltage drop on my 1999 3.0L sporadically for a while now. I will be driving and when applying brakes my radio will cut off and my voltage drops to 11.9v. Today while trying to trace wiring an exposed connection next to my coil pack unit touched and had a small spark. Before this, the truck would turn over and run, but after this issue the dash and radio receive power but nothing when I turn the key.

I have disconnected the battery in hopes of resetting something electrical with no luck. The dash shows the check gauge light but my code reader is not able to communicate with the PCM.

any thoughts of what I could trouble show to restore anything that may have been messed up?