AC Works great sometimes and then it doesn't

[WestLinnYukon]

My 2003 Yukon has gremlins and maybe you can help me out. AC works great blows super cold sometimes for 10 minutes, sometimes for two hours, then it start blowing hot air, again sometimes for 10 minutes and sometimes for an hour, and then it will blow cold again. All in the same trip. This is true in Auto mode, Manual mode and affect front and back at the same time. Refrigerant is at the right level, and I can not cause it to happen by changing temp etc. I thought turning car on and off would help, but it doesn't always help. Almost thought maybe the condenser was plugged because I don't notice dripping water, but might be its just never working when I get home and park it.

Any thoughts would be much appreciated.

 

[shawnbassee]

I’ve had an issue like this on my dads 2013 camaro, ac would work intermittently. Ended up being the TXV valve getting stuck or something of that nature.

 

[clandr1]

My guess is your temperature blend door actuator is going bad. On occasion my truck will start blowing hot air no matter what temperature I dial in. If I shut it off and restart it, it starts blowing cold again. I'm assuming my actuator fails and flops to the hot side, but the restart typically resolves my issue.

 

[Doubeleive]

the digital control can go bad and cause this issue
problem is a replacement unit even a dorman is stupid expensive $200 or so
and used ones look like someone has fingered it 24/7 for the last 100k
I would at least verify the problem before even trying to replace it becuase they are intermittent there is no reliable test
but you could pull over and pop the hood and look and see if the ac clutch is engaging or not and you can take the plastic cover off under the passenger side glove box and visually see if the blend door has in fact moved or not. (it has notches indicating position), look at the position when it is in fact blowing cold air and notate it. then when it stops blowing cold air check it again.
you want to do this when the problem happens, do not cycle the key, shut it off, etc. pull over and look

 

[SilverSport]

are you using the RECIRC button when this happens???...mine did this for the ride home after I bought it but I read somewhere that the issue doesn't rear its ugly head when just using the regular (outside air or flow through) air conditioning button (snowflake)...

Since using the regular air con button, I've not noticed this issue...hope this helps

Bill

 

[clandr1]

FWIW, I have factory electric fans and I notice AC temp increases when idling compared to moving/driving as well, regardless of whether recirc is on or not. Not sure if my condenser is just old and could use a replacement, or if it's just inherent to the nature of how automotive AC works. I recall in 2003 my girlfriend drove a brand new Honda Civic, and her AC would get warmer at a stop as well.

 

[OR VietVet]

Numerous possibilities here. The blend door actuator mentioned by @clandr1, the control head mentioned by @Doubeleive, recirc button problems mentioned by @SilverSport and whatever a TXV valve is mentioned by @shawnbassee. Sounds to me like the system is freezing up and then thawing out. I would, again just my opinion, replace the orifice, accumulator and while opened up flush what you can and check for restrictions and evac for 2 hours and recharge.

 

[Marky Dissod]

FWIW, I have factory electric fans and I notice AC temp increases when idling compared to moving/driving as well, regardless of whether recirc is on or not.
Not sure if my condenser is just old and could use a replacement, or if it's just inherent to the nature of how automotive AC works.
I recall in 2003 my girlfriend drove a brand new Honda Civic, and her AC would get warmer at a stop as well.

The far more likely reason is that GM / Honda / whatever car company programmed the fan-on thresholds hotter than the temp achieved cruising @ 25MpH or 45MpH to ever-so-slightly improve city MpG.

The first reason - not the most important, or the most fun, but the first reason - for an aftermarket ecm tune is to lower the fan-on thresholds so that the engine coolant temp behaves more consistently regardless of driving environment.