1966 Valiant Engine wiring harness
If the connector at the dimmer switch was backprobed, then there is a small current getting through to the lamps, but not strong enough to make the filaments glow. In which case it could be a poor connection at or inside the headlight switch.
With this scenario, measuring the voltage at the alternator's batt terminal will reveal the voltage at the main splice.
If the connector at the dimmer switch was backprobed, then there is a small current getting through to the lamps, but not strong enough to make the filaments glow. In which case it could be a poor connection at or inside the headlight switch.
With this scenario, measuring the voltage at the alternator's batt terminal will reveal the voltage at the main splice.