A.c. compressor stays engaged all the time?

[The motor guy]

I noticed the new compressor they put on my truck last year doesn't cycle on and off. Thought it was a little odd. There aren't any issues, all the other compressors on vehicles you hear them click on and off. Mine stays spinning the whole time.

 

[krismoriah72]

Try it on a cool day and see.. its supply and demand. Your location says Houston TX.. so the compressor will stay on until its job is finished which is never on hot summer days.

 

[The_Nuke]

I had this same concern about a previous Challenger's compressor operation, and I posted a similar question up on the CT site to clear up the what/why/whens of the situation. I don't remember the exact response, but basically it was explained that some a/c systems will require the compressor to stay running almost all the time. For those, the behavior you observe is okay. For the others, where it kicks on and off at varying intervals, the behavior you observe would NOT necessarily be okay.

If I'm not mistaken, I am pretty sure the Dodge a/c system in your truck (the 2007 diesel) should cycle on and pretty much stay on until there is a reason that the computer should command it to turn off (evaporator is freezing up, pressure too high) or the car ignition is turned off. If that is the case, your truck's behavior seems to be normal.

I can remember the kind of system that would always cycle on and off, and I think that is a design from the past which is slowly being phased out. But I could certainly be mistaken there. If I am wrong on any of this, I hope someone will chime in and correct me so we can all be on the same page!

 

[SteveSRT8]

All of our GM fleet trucks and service vans cycle the compressor if on lower fan speeds. At higher demand they will stay engaged all the time.

These vehicles run from 06 thru 18's, so the idea that it is being phased out may be a bit off...

 

[exranger06]

Unplug the electrical connector on the compressor and see if it disengages then. If it doesn't, there's something wrong with the clutch. If it does, it's working fine.

 

[Warstud]

Try setting the temp only a few degrees lower than the outside temp.... then see what it does.

 

[The motor guy]

All I k ow is it works [censored] good. It will freeze me out of the cabin when its 100 outside.

 

[mclasser]

Originally Posted by motor_oil_madman
All I k ow is it works [censored] good. It will freeze me out of the cabin when its 100 outside.

That's all that matters

 

[Nick1994]

Originally Posted by krismoriah72
Try it on a cool day and see.. its supply and demand. Your location says Houston TX.. so the compressor will stay on until its job is finished which is never on hot summer days.


Once the A/C cools down it shouldn't matter with the outside temp.

115 degree days and my Jeep still cycles the compressor.

 

[xxch4osxx]

The compressor on my Ram seems to stay on all the time when I turn the a/c on. I heard they have a variable displacement compressor and that might have something to do with it? Not sure though.

 

[The motor guy]

I recall the original compressor cycled on and off frequently and it had done it since nearly new. I wonder if it was never filled all the way with freon from the factory.

 

[clinebarger]

Fixed displacement compressor coupled with a Orifice Tube will stay engaged most of the time on hot days, My diesel truck uses a similar system.
Variable displacement compressor coupled with a TXV (Thermal Expansion Valve) will cycle, My Avalon has such a system & cycles a bit.