Engine Fan Comes With Ac

[Bump]

07 Yukon XL engine fan comes on on high everytime AC is turned on regardless of engine temperature. The fan will shut off when the truck reaches operating temperature. This will happen on a cold engine first

start of the day and all day.

[93gmc$$]

07 Yukon XL engine fan comes on on high everytime AC is turned on regardless of engine temperature. The fan will shut off when the truck reaches operating temperature. This will happen on a cold engine first

start of the day and all day.

 

 

The fan must be ON when the A/C is on or the system will overpressurize and fail (trust me). Don't know why it is shutting off later...

[DwayneJ]

The fan is used to cool the AC condensor which is in front of the radiator.

[jro909]

not trying to thread jack but why does my clutch fan come on when my a/c is on? (04 half tone 5.3 motor)

[asc08]

not trying to thread jack but why does my clutch fan come on when my a/c is on? (04 half tone 5.3 motor)

JRO -

I believe the clutch fan has a temperature sensing element in it. The warmer the air flow, the more the fan turns. With the AC on, it is probably raising the temperature of the air hitting the clutch assembly, and raising the speed of the fan. I would imagine that it will not come on to full speed as soon as you turn the AC on, but rather come on gradually as the air heats up.

[Bump]

I think the electric fan is two speed and mine, 07 Yukon, will come on in the high speed with outside temperatures of 70 degrees and a cold engine. I could understand if the engine temps were above normal operating levels and it was 95 degrees outside.

[redvett]

The cooling fan must come on when th A/C is turned on to pull air through the condenser. No air flow no cooling.

[wavery]

The cooling fan must come on when th A/C is turned on to pull air through the condenser. No air flow no cooling.

redvett is exactly right. When you turn on the AC, there is a switch that turns on the engine fan.

 

Fan clutches are temp driven as asc08 stated. The clutch has a large coil spring it it that tightens up the clutch as the temp heats up.. The fan is always turning which causes a small amount of air flow, even when cold but the fan turns faster as the air temp heats up and will eventually lock up on a hot day.

[Bump]

I don't think electric fans have a clutch.

[Doug_Scott]

I don't think electric fans have a clutch.

 

There are two discussions going on here, one in regards to the electric fan, and the other in regards to the mechanical fan with a bi-metalic spring type "clutch".

[zedbear]

You'll know it when a clutch fan engages fully. It is loud and you can feel the drag from it. Mine is engaged fully around 212F coolant temp.