Engine fan staying on

[Brock]

08 prostar isx 871.

I've had the fan stay on before but engine codes came up as it was a wiring issue but now there is no codes. What would cause the fan to stay on? Cold as balls so I sure as hell am not using the ac.

[marek4792]

You could have a bad solenoid switch.

[Brock]

(02-18-2017 )marek4792 Wrote:  You could have a bad solenoid switch.

I was thinking that. Do.you know how to verify this?

[snailexpress]

(02-18-2017 )Brock Wrote:  

(02-18-2017 )marek4792 Wrote:  You could have a bad solenoid switch.

I was thinking that. Do.you know how to verify this?

Engine not running, ignition ON, air pressure is full. Pull out air tube from fan clutch. If air starts blowing from tube the sensor, solenoid, wires are intact.

[Magard]

I would look around at the pressure switches on the ac. Ac pump is on when defroster is on. Trying to dry air out through condensation. Sounds crazy but a easy place to check. Could be a bad pressure switch on ac also. Check on the pressure side. That should default to fan on if you unplug pressure switch or switch goes bad.

[Rawze]

(02-18-2017 )Brock Wrote:  08 prostar isx 871.

I've had the fan stay on before but engine codes came up as it was a wiring issue but now there is no codes. What would cause the fan to stay on? Cold as balls so I sure as hell am not using the ac.

simply unplugging the A/C pressure switch makes the engine fan come on and stay on. Hence, if you have a bad pressure switch, bad plug, wiring, etc.


{correction - A/C at zero pressure does not make fan stay on, only if there is bad connection to pressure switch does}.

[Magard]

I don't know on pro star but other trucks I've had. The system being low didn't make the fan come on. Just had to throw that out there. Maybe pro star is different. If the fan comes on when empty then it could be low pressure switch is unplugged or bad also.

[Brock]

My ac hasn't worked in years. Line rotted out, zero pressure in there.

[Magard]

I guess I'm barking up the wrong tree agian.