AC Randomly Stops Blowing Cold

[Doubeleive]

th

the part numbers are all the same part, the 1st one being the most current, gm changes part number like underwear

 

[Doubeleive]

This behavior is generally indicative of being low on refrigerant.

Those cans with gauges cause lots of problems, it is best to use a manifold to introduce refrigerant by weight after discharging and vacuuming the system.

James on these k2's if the temperature sensor is goofy it "can" cause the fans to run after the vehicle is shut off (which yes that can be commanded to do under normal operation) if the temperature is high.
but if the sensor is reading incorrectly it also makes it happen when it shouldn't, for instance if it was going to happen to anyone (from being hot after shut off) it would be me and it never has and it certainly wouldn't do it all the time. the erratic ac operation is also symptom of the temp sensor being goofy also it has been reported a number of times.
1. fans running after engine off
2. fans running high speed at cold start or constantly throughout the day
3. error messages saying engine hot ac turned off (when the engine is not hot, and/or gauge says normal)
4. incorrect temperature gauge readings, too cold, too hot, gauge pegged either way
the temp sensor's go goofy and the thermostats get stuck or do not operate correctly also.
it very could still be low refrigerant, but that wouldn't cause the fans to run after the engine is shut off
there is some low-key association with the temp sensor/fans/ac, I think it has to hit a certain parameter to throw a code, like if the temp sensor fails x amount of times in a row
some people have also reported disconnecting the battery sometimes corrects it for a week or two, then it fails again. that tells me these temp sensor are apparently borderline when they go bad.

 

[swathdiver]

it very could still be low refrigerant, but that wouldn't cause the fans to run after the engine is shut off

I don't know the answer to that one. I had this happen to us with a Pontiac and don't recall the fans running afterwards but that was some time ago and this may be a specific K2 thing like you said.

 

[nokuy]

Changed coolant temp sensor & thermostat. Reconnected battery and all is functioning as it should now. Temp right at 210°F, no noisy fan & A/C blowing cold.

 

[Doubeleive]

Changed coolant temp sensor & thermostat. Reconnected battery and all is functioning as it should now. Temp right at 210°F, no noisy fan & A/C blowing cold.

NICE

 

[nokuy]

NICE

So now another issue has presented itself. The outside air temperature says that it’s 32°F. ‍ I don’t know if this will resolve itself and is maybe due to having the battery disconnected. Or is a new sensor in order?

 

[nokuy]

So now another issue has presented itself. The outside air temperature says that it’s 32°F. ‍ I don’t know if this will resolve itself and is maybe due to having the battery disconnected. Or is a new sensor in order?

Welp, a little interweb search found this:

https://static.nhtsa.gov/odi/tsbs/2016/MC-10119027-9999.pdf

Looks like it’ll sort itself out.

 

[Doubeleive]

So now another issue has presented itself. The outside air temperature says that it’s 32°F. ‍ I don’t know if this will resolve itself and is maybe due to having the battery disconnected. Or is a new sensor in order?

that happens when the battery is disconnected, just go drive it 5 miles on the highway it should self adjust automatically correct before the 5 miles up

 

[SubTX]

I want to add more info to this type of issue and another scenario with a different possible solution. I have the same symptoms, fans run, ac doesn't work but then it all suddenly works. I've changed the temp sensor and the AC pressure switch as well as put gages on the AC (all fine) and it didn't make a difference. I worked to trace the controls path and finally found where the AC clutch relay is. It's a solid state relay that is on a PC board. That board is the base for the engine fuse box. The fuses and relays connect on the top and the wiring connectors plug into the bottom. At first I thought the relay was dying but then I learned something else.

I only recently had a correlation of seeing the temp gage in the dash go completely dead, fans go on and the AC stops working. I pulled the power from the engine fuse box for a minute and reconnected. After that it took 3 tries (on off with the key) to get the dash display to turn on. Once I started the car the temp gage worked and so did the AC. These seem to be symptoms of a Body Control Module failure. I'm now in the process of getting a BCM and having it programed. Hopefully I can get it done by next week and I'll update.