it has probably moved and is reading the temp in the engine bay. The sensor should be located near the drivers foglight in the brake duct. I have the opposite problem. Mine sometimes comes loose and dangles beneath the car, and when I go through a water puddle the temp drops nearly 10-15 degress.
<span style='color:gray'><span style='font-family:Courier'>1995 e36 3 Series RIP
1999 e46 3 Series BURN IN HELL
2000 MR-S Roadster= Current</span></span>