DASH LIGHTS
Now to your question about the dash lights.
The instrument lights, radio light, and similar options are a branch from the parking and tail light circuit.
That branch occurs inside the headlight switch.
-> Power goes in the B2 terminal and then can split off through the dimmer control.
- > Power then goes out the I terminal to the 3 amp fuse in the fuse box.
-> Power leaves the fusebox on an 18 or 20 gage orange wire(s) going to the instrument & radio lamps.
To figure out why its not turning off, one approach might be to check for power at the 3 amp fuse. If its has voltage, pop the fuse. If the side feeding the lamps still have power - then its a cross wire short. If only the input side has power, then its headliught switch or wire going out of it.
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