The Stovebolt Site Forums The Shop Area The Electrical Bay Hi Beam Indicator Light

I am finishing the last of outstanding items to complete the restoration of my '53 GMC short bed, keeping the original 6 volt, positive ground circuitry. The previous owner had purchased a pre-made wiring harness which when installed presented no significant problems (although the wiring color codes did not always match original) but the hi beam indicator light stays on when switching from hi to lo beam. As part of the restore I installed a new dimmer switch and replaced both headlights. I have reviewed the threads I could find on this problem and tried the suggestions provided but the problem persists regardless of what I tried, even trying a new dimmer switch. My last attempt has been isolating the left light from the main wiring harness, with jumpers to the headlight pigtail that attaches to the left fender terminal strip, including a jumper to the positive ground frame connection. Switching from lo to hi and back, the indicator light does dim slightly but is always on. The voltages measured at the terminals on the dimmer switch clearly shows why the light stays on but I am baffled as to why there is voltage on each of the hi and lo beam terminals for the headlight harness.
Battery voltage is 6.2 volts. Voltage from the light switch is 4.9 volts when switched to hi beam and the hi beam terminal is 4.8 volts and lo 4.7 volts. Switching to Lo beam, the
voltage from the light switch increases to 5.1 volts, the hi beam terminal measures 3.1 volts and lo beam terminal 5.1 volts. I did check to be sure there is no contunuity between the two terminals on the terminal strip, it is also new. The wiring harness and connections conform to the schematic in the GMC Trucks Maintenance Manual except for one other mystery. The harness from the dimmer to the terminal strip for the hi beam is a blue wire. Another same color blue wire in the harness, connects the voltage regulator to the armature terminal on the generator and there is continuity between the two wires, which does not conform to the manual schematic, but disconnecting the wire to the generator does not change the voltages measured on the dimmer switch terminals. I assumed from the schematic that the hi and lo beams were powered by two circuits from the dimmer. I was told that is not the case, that the three terminals on the back of the headlight are all at the same voltage and the circuits are made when the dimmer switch changes one to ground to complete the circuit. If that is the case where in the circuit does the connection to ground take place? The ground wire from the headlight bucket attached to the fender does break the circuit when lifted, so it is part of the circuit. As I said, I am baffled, it can't be this complicated.