[DaleM]

For the past year or so my dash lights have been pretty dim but since I do *most* of my driving in the daytime, I never really much cared. A few days ago I noticed no dash lights at all regardless of the headlamp switch position (parking lamps or full). I also noticed my dome light doesn't come on when I turn the knob full left although I can feel the resistance at the full left (counter clockwise) position when the dome lamp *should* come on.

The dome lamp does work when the door is opened so I know that's good. Instrument panel fuze check out OK with an ohm meter.

The headlamp switch does seem a bit sloppy when turned from one extreme to the other. All other lights work as they should; headlamp both dim and bright, turn indicator and lamps, brake lights, etc.

Any other areas to check or does it sound like the rheostat (maybe) in the switch itself?

 

[John_Muha]

The dash lamp fuse is the output from the rheostat. Moving the rheostat changes the voltage, to ground, on the dash lamp fuse. It should come up to near the BAT voltage as you move the rheostat to the one side. Might peek at that.
The "click" or the detent portion of the rheostat grounds the white wire. (I assume white because that's the normal color for the dome light). When the rheostat is clicked, white is shorted to the frame of the headlight switch. The switch frame must be grounded. On plastic dashes the switch goes through a large eyelet lug which provides ground to the frame. Metal dashes rely on the dash being grounded. Later model switches have a seperate ground pin on the connector. I used one like this in my 64. The original connector goes on and misses the frame ground pin so it works the same way as the original did. Took the almost new one out of a 77(?) Nova.