Thanks for all of the info, everyone. It started working right again, running the fan when it should and turning it off otherwise, keeping the temperature (per the code reader and gauge) within a few degrees of 190F (88C) even in hot weather and when pulling long hills. I am sure it will act up agai...

Would I need to remove the sensor to test it? I am guessing so, because I think I will need to do something (perhaps take it to higher than normal operating temperature) to make it fail now; just driving it normally hasn’t made the gauge display anything unusual since my test drive the other day whe...

Hi everyone! The other day the radiator fan in my 2004 S60 (2.4, non-turbo) didn't turn off and ran the battery down. The fan would run whenever the battery was connected, even if the key was not turned on. At first we worked around it by disconnecting the battery whenever the car was turned off, an...