Temp Gage Pegs When I Step on the Brake?
 

With the key off, I noticed yesterday that the temp gage reads full-scale when I step on the brake. What does this mean? It may have been doing this the whole time I've owned the truck (early March) since I'm not in the habit of looking at the instruments with the key off, so I don't know if this is a new thing. Please, could someone let me know soon if this might be a harmful/ hazardous condition? I have to use the truck for a long tow on Monday. Thanks very much for any help!
- Chris

sounds to me like you have a bad ground.

Or maybe a short between the brake light circuit to the temp gauge circuit.

Hmmm. I'll reintroduce myself to my multimeter. Thanks, guys!
- Chris