On a road trip to the Grand Canyon today. AC was working fine for at least 5 hrs - blowing cold. Suddenly I noticed the air coming from the vents was no longer cool. Fan was working as expected, but air was warm. Tried various settings, as well as, turning it off for a while. No joy. Is there a fuse that would control the compressor? I did not bring the owner's manual with me and the fuse covers are not marked. Can't find an online copy of the owner's manual. Driving my 991.2. TIA

 

I would check your condensers for rock impact damage. It’s possible you could have lost your refrigerant.

 

+1 for this. Apparently quite common -- there's a reason people buy those $220 grills!

 

Agreed on checking condensers for rock/object damage...such a poor design on these cars with no protection.

 

Here are fuse panel maps for your car.

https://fuse-box.info/porsche/porsch...017-2018-fuses

 

I had a slow leak. Each summer the a/c would slowly get worse and then die. Dealer couldn't figure it out. Said they dye tested and believed the leak was in the evaporator behind the center vents and they didn't want to tear out the whole interior. I didn't want them to either.

Local independent figured it out in 5 minutes - condenser damage from stones. They charged and turned on the system. Used a infrared thermometer gun they could see several hot spots coming from holes in the front condenser. Ordered and replaced the condenser. All good.

Indications: On startup a hissing noise was heard from the center console behind the center vents. As the refrigerant leaked, the length of time I heard the hissing noise increased. Next the passenger side vents would not be as cold as the driver's side vents. Eventually the passenger side would go warm and then not too long after, the driver's side would quit.

Good luck!

 

Two years into my 991.2 an ‘o’ ring failed and my AC stopped working.

Here’s the note. And, another discussion on the topic.

https://rennlist.com/forums/991/9310...l#post16639074

 

^ Some great inputs above, from stone damage to o-ring.

I'll add one more, which is prompted by your mention of Death Valley: Did a track day at Thunderhill a few years ago in blistering heat (108? 112?). So imagine the track temps. We were in groups of 991.2 Turbo/Ss, which sailed through the day without issue until the fourth and final 20-minute session. About halfway through, I noticed my air-conditioned seat was no longer cool (how spoiled we become…) at 145~ mph in the way into T1. When I looked down a few corners later, the blue lights on the button were off—but I remembered hitting the button before we left the pits. Just then, someone got on the radio to say his A/C was entirely kaput. All was fine in both cars when we left the track later for the drive back to civilization.

 

Pretty sad that the Porsche experts, who charge an arm and a leg, could not figure out the problems, but that the indy could - and for less money.

 

Do note that the "porsche experts" are by-the-book techs who follow Porsche's profit-optimized repair procedures, which err on the side of "just replace it" instead of actual repair work. The indy techs are the ones who actually take things apart for repair, and as such tend to have a much more intimate understanding of the cars.

 

Agree.

Porsche techs read computer codes and fix the code.

Indies take things apart and fix the root cause.

 

There are “change over valve” issues on the 991’s. Check that too as they affect heat and AC.

 

^ Only for as long as they're allowed to exist. Troubleshooters are an endangered species, sadly.

 

Had this issue with 991.2 - 2019, 14K miles. Didn't get the hissing sound though. Dealer replaced the drier and O rings. They aren't 100% positive this was the cause of the leak. Left dye in the system in case it happens again.

 

Three times back at the dealer for me was the charm. Problem showed up as no cool air from passenger side vents (the spousal unit was NOT happy). They tested the system and found it low on coolant (Freon?). After recharging with dye, they couldn't find a leak. Finally they realized that the valve where you put in the coolant was leaking! The valve is just a Schrader valve except you cannot unscrew and replace the inner plunger (?) as you can on your wheels. It requires replacing a whole unit. Oh well two years and cold air is still flowing (fingers crossed!).