AC compressor keepers cycling even when AC is turned off.

[Lemon-T]

Wondering if anyone else has experienced this. My 2005 Liberty Renegade’s AC compressor keeps cycling on and off even though I do not have the AC button on. It is Nov and I am running heat and it still cycles. With the gas milage in these already not good. I cannot imagine this is helping any.

 

[RenKJ]

is it staying on for a long time? its normal for it to cycle on for a short time to keep the system lubed

 

[Lemon-T]

is it staying on for a long time? its normal for it to cycle on for a short time to keep the system lubed

No. It just keeps going off and on every minute or so. But I finally found another post like mine on here and it seems that it does it when it’s set to defrost, defrost/floor and of course when the AC snowflake button is on. To keep the air coming in dry so it doesn’t fog up the windows. So I guess it’s normal? IDK. It seems to lower my RPMs a bit. So I was worried it was contributing to my worse than normal gas milage. lol

Most likely MPG is worse because of age. lol. “It’s a Jeep thing” strike again I guess. Ty for responding.

 

[RenKJ]

no worries, yes it has to run for defrost I think, if it was stuck on all the time then you need a new AC clutch

for mileage, driving style, fuel cleaning and spark changes are important

 

[CheddarGau]

No. It just keeps going off and on every minute or so. But I finally found another post like mine on here and it seems that it does it when it’s set to defrost, defrost/floor and of course when the AC snowflake button is on. To keep the air coming in dry so it doesn’t fog up the windows. So I guess it’s normal? IDK. It seems to lower my RPMs a bit. So I was worried it was contributing to my worse than normal gas milage. lol

Most likely MPG is worse because of age. lol. “It’s a Jeep thing” strike again I guess. Ty for responding.

AC runs when vehicle is in defrost mode even if no AC light is on. AC is very good at pulling moisture from air, which defrost windshield way faster, which is why they (by they i mean every brand)do it that way.

 

[Ocelot]

There should also be a low ambient temperature cut-out that takes this feature out if it's cold out (A/C doesn't perform at low temperatures, nor is it any good for it).

 

[HVACMAN]

Wondering if anyone else has experienced this. My 2005 Liberty Renegade’s AC compressor keeps cycling on and off even though I do not have the AC button on. It is Nov and I am running heat and it still cycles. With the gas milage in these already not good. I cannot imagine this is helping any.

All of the previous answers are correct for how it is supposed to operate.
Our 2005 on the other hand runs the compressor when in the heat/floor position which is not correct. This is a known Common problem that I recall seeing discussed on forums in the past.
There was a solution as well, but I never pursued it.

 

[Legacy]

I have a 2005 Liberty and the AC compressor would cycle on and off as noted in this thread. The easiest workaround I found is to simply remove the compressor fuse located under the hood during cold weather. I make a note to myself to install the fuse every month or so before taking the car out on the road. When I return home I simply remove the fuse. This way I am lubing the AC system periodically while not having to put up with the compressor cycling every time I drive the car.

 

[Robochop]

I agree with everyone else. When you have the defroster on, it cycles the A/C. I want to to say it won't cut the A/C on if you turn up the heat control to hot?

 

[Celticlady]

How about a link to that solution??!!

 

[Celticlady]

There should also be a low ambient temperature cut-out that takes this feature out if it's cold out (A/C doesn't perform at low temperatures, nor is it any good for it).

Yes. Cycles All the time. Regardless of switch position. Regardless of what I do to it. Or How many times i have taken it to ac specialty shops. 06.

I have not thought of pulling the fuse.

 

[WWDiesel]

There is a modification to change it so the AC compressor only runs when you have the AC button selected.
BE WARNED: This modification requires removing the AC dash panel and modifying the back of HVAC Switch.
(NOTE: I have personally done this on my 05 Jeep and can testify that it works as described)

AC SWITCH PANEL MODIFICATION
(to limit AC compressor to only run when AC Switch is depressed/active)

1) Remove the HVAC control head from the vehicle. Very easy to do, if you have problems with this part, stop here! :wink:
2) Remove the control head from the bezel by removing the 4 screws.
3) Remove the white cover from the back of the control head. DO NOT remove the vacuum switch attached to the back of the white cover, it will come off along with the cover just fine. There are 3 screws and about 8 snaps that you must carefully work to remove the white cover.
4) Make 2 separate cuts in the copper strip where shown in the attached picture. I used a small pick to elevate the strips very slightly and cut them with wire cutters. Be careful not to rip the strip off the plastic attach points. I cut out a fairly large piece at each place, but it is up to you how big a chunk you want to cut out.
5) Solder an insulated wire from the post as shown on the picture, to a place just before where the connector is. Leave some room for when the white plastic cover is reinstalled. The wire shouldn't have to be a very heavy gage. I used a computer CD audio wire because of the nice cover on it.
6) Reinstall the white cover on the control unit, making sure the vacuum control valve is lined up and engaged properly. Make sure the wire that you just soldered in is not hitting any movable parts in the head, or is getting smashed into the top circuit board.
7) Reconnect all the HVAC control wiring (but not the vacuum lines) and test it's operation. You can do this without installing it onto the bezel for testing. The A/C compressor should now only come on when you press the A/C button, and not any other time.
8) If it works, reassemble the controller back into the bezel and the vehicle.

**If it does not work, check all the steps carefully. Make sure the cuts and wire attach points look just like the picture. You can always solder your cuts closed and remove your installed wire to put it back to original operation if you desire.

**Just a word of warning if you do this mod. Make sure you periodically run your compressor throughout the winter months to make sure the seals in the A/C system get lubed periodically and does not dry out!

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[sota]

I still need to hunt down the reason why my evap keep freezing over.

 

[Celticlady]

I was going to reply earlier but got distracted.

Any time a evaporator (car or house same)freezes over look these

1) low freon
2) reduced air flow.

In a house that usually means dirty air filter. Little more complicated on a car.

In a car:
blend doors are not working right. Recirculation doors not working right.
Look for mouse nest in your system.
Fan resistor burned out.

Make sure the plug on the back of the control head is properly seated.

 

[sota]

Yep, done all that.
refridgerant is 5x5.
air flow is massive, until the evap frosts over obviously.
if I keep the blower at 3 or 4 it'll usually NOT frost over.
my solution right now is I unplug the compressor clutch in the winter.
sucky part is, it'll frost over in 90deg weather!

it's pissed off at something, damn if I can figure out what.

 

[Celticlady]

Yep, done all that.
refridgerant is 5x5.
air flow is massive, until the evap frosts over obviously.
if I keep the blower at 3 or 4 it'll usually NOT frost over.
my solution right now is I unplug the compressor clutch in the winter.
sucky part is, it'll frost over in 90deg weather!

it's pissed off at something, damn if I can figure out what.

You didn't feed the gremlins

IDK.

I tried "the unplugging the compressor" when traveling from CA to OK in February to get better mileage. Fried the controller. Yes, I had the batter disconnected and the AC off

 

[sota]

dunno how you could fry anything, unplugging the clutch.

 

[Celticlady]

I don't disagree. Been turning wrenches sinch 9 years old. 70 now. Still doing it.

Yes that surprised the heck out of me. This whole ac system in this liberty was designed by a drunk. It makes no sense at all.

 

[JeepJeepster]

On the 02-04, the compressor will kick on in both defrost positions.. On 05 and up KJ's, it will also kick on in the floor position.

Many years, ago, I put an 05 and up HVAC controller in my 04KJ so I could independently control the A/C. I took it apart and put black tape over the contacts that turn the A/C on, no need to cut or solder anything.

Check the low pressure switch for a freezing up evap.

 

[RenKJ]

for consideration, I've read that vehicle A/C compressors need to run every once in a while to stay properly lubed (the refrigerant is also the lubricant) so be warned if you disable your A/C clutch for a long time