Fan runs continuously


New member
"01 379, Cat C15, My fan runs continuously. I've change the solenoid on the firewall, and had it checked out. When the A/C plug is removed the solenoid which is "normally open" closes and the fan shuts down, when it's reconnected it fires back up. Same thing happens with the temp plug at the thermostat housing is disconnected and reconnected. There is power to the plug on the solenoid when it is disconnected and it loses power when reconnected. The dash switch is also functioning as is should. Anybody got any ideas?



Well-known member
I would start at the A/C high pressure/fan switch. Replace the switch and the pins in the connector. They are notorious for loosing connection. Note- There is a timer in CAT to delay Fan on /off time to help save the fan clutch so it may take a minute or two to respond and turn off depending on what the timer is set to. Sometimes if you simply push over one way or the other on the connector and hold it for a while and wait it'll turn off. Then you found your issue.