Bypass the switch
Reply #8 –
Do we mean the dimmer SWITCH for the headlights, or the dimmer WHEEL for the gauges? When the lights are off, the radio, clock and speedo get full power. When the lights are turned on, the other dash lights (gauges, heater panel, etc.) are brought into the circuit, and the "cluster illumination relay" switches the supply side to fuse #13, via the probably-broken-wire rheostat behind the dimmer WHEEL in the main headlight switch.