Obviously he has a bad part in the system. He should have found the bad part first then clean up the wiring after. Now he has no clue what to do because he has disturbed all the wires. Start back a square one if possible and go from there.
Not really arguing here..... As an FYI, this car has a bit of a history of low voltages and wiring issues, going back a while. Symptom descriptions pointed to voltage issues at the beginning of this round, so that was tackled.