That's what I'd go with. best guess, seen the same thing numerous times, usually in the dimmer mechanism in the headlight switch. It can also melt down the headlight switch connector.
The wire for the instrument cluster lights goes from the parking light fuse, up to the headlight/dimmer, back down to the instrument light fuse and back up to the instrument cluster. I had one, rub through, which cut the harness on a sheet metal seem. I bypassed the dimmer circuit and ran a wire directly up to the cluster from the instrument fuse, always bright instrument lights, but much easier than trying to deal with that harness. That harness is really stuffed in there tight, the possibility to do more damage than good, is what convinced me to bypass the whole thing.
Don't forget the clock, it can also short out the dimmer circuit. Easy to pinch a wire in there and cause a short or the clock itself can short out. Have you been in the sound system lately or the HVAC controls, easy to pinch that clock wire.
The real bummer is the replacement switches tend to fail fast, even OEM, the quality has gone way down.
One thing to check is that the headlight knob is seated all the way in, it runs through a stack of contact discs and you can get the knob rod part way in and it will work after a fashion. I always push the release button, push the knob all the way in and moderately smack it with the palm of my hand. If you hit it too hard and the discs aren't lined up, it may damage it. Twisting it a little left and right, while pushing with the release button pressed may be a better option than my smack and pray technique.:gee:
