24 volt 1979 Canadian bj40 with 3B diesel. PO did a PAINLESS rewire of the entire vehicle. Passenger headlights work perfect on both high and low beams. Driver side has good low beam but nothing on high. Removed headlight and it bench test good on both filaments. Voltage at the connector was 8 volts for the high beam—should have been 12 for driver side. So now I am searching for reasons for this voltage drop. Corroded dimmer relay contacts? What else can I check? Any other ideas?