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AC cycles from cold to cool back to cold every 10 seconds or so...

5K views 15 replies 14 participants last post by  WK2OverlandII 
#1 ·
The other day it was about 90 and sunny and I had the AC on Auto, set to about 66F or so - so the fans were running at high speed. I had them pointed at my hands and face and noticed that the air coming out would be very cold for about 10 seconds or less, and then the air would become just cool for about the same period of time, then it would become cold again, and this kept repeating the entire time.

I turned off Auto mode and the same thing occurred.

Is this normal / does anyone else's do this? My 3-year warranty expired, so I hope so. I know my AC has always made the "darth vader" noise about every 10 seconds (wondering if it's related) but I'm not sure it's always done this - although it could simply be because I never used to point the vents at my hands and face so I didn't notice the temperature fluctuation (although I have also always noticed that my AC's performance has always been underwhelming).
 
#2 ·
I've had that frustration with the jeep climate control since I bought it. It's been inferior to my Ford sport trac's previous climate control in that regard exactly. I notice it on road trips even when it's not pointed at my face, it's uncomfortable. I find it also either hot or cold when selecting temperatures instead of modifying the air temp coming from the vents
 
#4 ·
I'm on my second '16 WK2, both exhibit this behavior and it drives me nuts now that it's approaching 100 in Texas - couple this with the fact that the pano roof is essentially a radiant heater and I'm not so happy. I can't imagine this is some design fault. The AC compressor is either on and cooling or turning off for a split second and dropping pressure causing this.

I am never comfortable in this car when the temps are over 90, not even at max AC. Did they even bother hot weather testing this car in its development stage?

Has anyone gotten this remedied?
 
#5 ·
Concerning the performance being underwhelming my 2014 was like that it cooled but did not cool well when it got fairly hot. I lived with it like that for around 2 years then took it in and they determined that it was undercharged from the factory. they charged to proper levels (under warranty)and its been fine the last year and a half.
 
#6 ·
FYI, starting in 2014, Jeep started using the new R-1234YA refrigerant that is a little less efficient than R-134A. I've been pretty underwhelmed with mine on the really hot days so far. I had them check it when I had the new shifter recall done, and they claimed it was blowing 47F on max A/C, in the shop, on an 80F day. They said that was within spec. I say BS!! I always keep a thermometer in the left vent of all my cars, and until this one, they would have no trouble getting down to 40F and under on Max or recirc. I have yet to see it go below 50 (they took their reading from the center vents). I think the system is capable of getting cold, it's just software making the compressor cycle off too soon. Maybe to keep it from freezing up in humid climates, I don't know.

I think all modern vehicles just don't blow the ice cold air they used to.
 
#7 · (Edited)
My 2014 GC must have made it right before the cut off I still have R-134a in mine. I thought R-134a was supposed to be the wonderful savior from the "evil" R-12. So now R-134a is the evil and R-1234YA is the savior? So that means the price of R-134a will start going through the roof like R-12 did? I smell a rat.
 
#8 ·
My old early built (2/2013) 2014 Summit has the R-134A refrigerant. The A/C in it never performed as well as the one in my previous 2012 Overland. About 2 years ago, I had the dealer check it, and it actually had 1.6 ozs. to much refrigerant. So they evacuated and recharged with the proper amount and while it's improved, it still doesn't work like it should. But since we don't get very hot temps (rarely above 80°) around here very often, it is ok for now.
 
#12 · (Edited)
The cycling is necessary to prevent freezing of the A/C compressor. Every car I've had does that. On the Subaru, it is pretty obvious because the compressor is belt driven and you can see its spinning-stopping cycle. Obviously when there is a high temperature differential between the outdoors and what you are trying to achieve inside the vehicle, this behavior will be felt at the vents.
 
#13 ·
Also, the electric fan failing to reach MAX rpms can cause the compressor to short cycle. If its not pulling enough heat off the condensor the high side pressure will be too high and thus compressor will cycle off. While sitting idling at operating temp with AC on the electric fan should be at full speed.
 
#16 ·
yes, I have a 2019 Ram 3500 Laramie and the dealer tested it and the middle vents are cooler than the ones by the doors by about 8-10 degrees.

Back in the early 80's my dad had my mother's AC in her 1975 Plymouth Valiant Brougham spitting ice it was around 37 degrees at the vent...that thing froze you out.

I know when my 2020 JGC Trailhawk V6 ESS kicks in the air coming out the vents is cool but not cold...once the engine re-fires it gets pretty cold.
 
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