I have a '64 Impala 2dr ht. and am new to this site. Several days ago the interior lights stopped working. I checked and found a blown fuse which was replaced. The lights are now working but will not shut off unless I pull the fuse. Up until the blown fuse everything was working the way it should have. Can you turn the interior lights on via the headlight switch? Would replacing the switch rectify the problem.
Any help is appreciated because I'm at the end of my rope.
I ran into an issue with my lights not turning off and it ended up being a grounding issue with the courtesy light under the dash. While working under the dash, I bumped the light on the passenger side enough for it to ground out. Took a while to figure it out, but once I moved the light slightly they went back off. So, I would check those lights an make sure you didn't accidentally bump them.
My first thought was the headlight switch as well Buzz. Normally you turn the headlight switch knob to the left (counter clockwise) and you can feel a small notch or indentation. It only moves a little bit. Any chance you turned it and didn't realize it?