Thanks for your thoughts and pictures Denny. I was hoping this switch was easily serviceable.

I haven't decided to re-wire the whole truck yet (emphasis on "yet"), so I'm going to roll with a few of these glitches until I am forced to make up my mind!

Here is another strange thing: my brake light seems to get brighter as I push the brake pedal down. I assumed the brake light switch was either on or off -- there should be no variation in light intensity. This kind of behavior makes me think there is corrosion and going on here, and in probably other places in my electrical system.

I like mechanical things, but I also like using my multimeter, so this will be a good opportunity to mess around with it.