The SO has been driving me 1999 Jeep Cherokee because it has air conditioning. She’s run into a situation where she’s using the a/c and the temperature gauge indicates overheating. There’s apparently a warning chime as well. Note that we’re in Northern Washington and it doesn’t get that hot here. When she turns the a/c off, the temperature gauge drops to normal immediately. Were the engine really overheating, the gauge would not drop like that, but drop gradually. I have not witnessed this problem, as I usually drive (the Prius) when we go out.
Any clues as to what’s happening?