Engine fan running

[Rawze]

(12-27-2017 )Rockycoon75 Wrote:  I have a 11 Pete with a 871. The engine fan is running constantly. Hooked up insite and it shows it's in ac mode. Threw my gauges on there and I only have 45 psi on the low side. The AC is working fine when I turn it on.
If I shut the truck off and turn the key back on the fan releases and free spins. As soon as I start it back up it goes back to locked in. Doesn't matter if the A.C. is off or on. I even tried pulling the A.C. relay. I thought maybe a switch at first but don't understand why it would only be bad with truck running.

some history? when did it start doing this? have you re-filled the system with refrigerant? have you replaced the high pressure switch? have you checked for corroded wiring on the high pressure switch?

Have you disconnected all batteries for 30 min to reset the cab control?