A/C compressor cycles when off....

[Suprdave1]

I was getting ready to flush my heater core due to it blowing cold air. I was checking the vacuum lines with the engine running when I noticed the A/C compressor cycling with the A/C control in the off position. Is this normal? I also found an actuator under the glove compartment that doesn't appear to move when the heater controls are moved.
Thanks

 

[ma96782]

For my .02.

When your control is "off," the AC Compressor should NOT activate.

The only time it will activate (other then when on AC) is when it's set to defrost.

Aloha, Mark

 

[BrooklynBay]

Welcome to this forum! Are you referring to the blend door actuator?

 

[Suprdave1]

Not, sure, but I did check the blend door thing according to the pinned posting and mine seems to be correct. Not sure what the actuator does that I was watching, but its right under the glove box on the right. It doesn't move when I move any of the heater controls, but I can move it manually.

 

[ma96782]

Most times when you slide the control to the heater position, you'll hear the door go "thunk."

Anyway.......since you are having heating issues. Go through the heating system since you're in the mood to fix stuff.

The typical heater system is usually pretty simple.

The heater system for the cab is fed by heater hoses from the water pump (and/or motor) connected to a heater (looks like a small radiator). The heater, exchanges the engine's heat with the air that passes over the heater's fins. For additional comfort, air can be provided by a blower fan motor. And, various doors regulate how much of the air is mixed with the outside air and/or how much heated air gets to you in the cab.

Aloha, Mark

 

[manaen]

I was checking the vacuum lines with the engine running when I noticed the A/C compressor cycling with the A/C control in the off position. Is this normal?

the AC pump will also engage when the heat is set to defrost, floor, or any of those combination's. Vent is the only mode that blows heat and does not engage the AC pump. The AC helps to dry the air which makes the defrost work much better.

 

[Suprdave1]

the AC pump will also engage when the heat is set to defrost, floor, or any of those combination's. Vent is the only mode that blows heat and does not engage the AC pump. The AC helps to dry the air which makes the defrost work much better.

Let me check it again!!

 

[Suprdave1]

OK, did it all...checked heater hoses, both hot, removed cover for heater core, it is hot, no leaks and was replaced a couple of years ago. Checked the blend door, works fine, still blows cool air. With the engine running the only time the A/C clutch cycles is when it's either on or on defrost. Sounds correct. With the cover off the heater core I turn on the fan and feel cool/cold air at the top from some where, but warmerat the bottom. Still too cool to heat the truck or deice the windshield. WTH????