2014 Silverado crew cab air conditioner issues

[Air2Air]

Any ideas would be appreciated. I am a mechanic so I know a little about vehicles but this has me stumped. I have a 2014 Silverado with 177k. The truck is well taken care of and doesn’t have any of the issues common to these models. About a months ago I noticed my a/c wasn’t as cold as it normally runs but it’s not been terribly hot so I didn’t think much about it. Now that it’s hot I really need it. It’s not blowing hot air but more ambient temp air. I took it to a local shop and they did a Freon recovery, vacuum check and refill. It was a tad low but not enough to effect cooling. 

Here’s a list of what we’ve checked:

A/C system pressure good (according to mechanic)

Compressor functioning properly

Blower fan good

A/C control head unit functioning properly

All blend doors functioning properly

 

Here’s what we’ve found so far that may be the culprit:

Scan tool found codes U1509 and U0020

Engine cooling fans not cutting on when compressor engages

 

I have found little info on those codes but a U1509 could be a A/C control module. I’m curious if this could be as simple as a stuck expansion valve or system blockage or if it’s more of the sparky gremlins from GM. 
I’m heading out now to retest the pressures and see if possibly it’s a TXV and do a hot water test on it.

Will keep you posted.

UPDATE: I used my own gauges and rechecked the pressures. After letting the engine warm to operating temp my low pressure side was reading 60 psi and my high side was reading 60 psi. I let the system run for about 45 minutes and the low side increased to 75 psi and high side remained at about 65-70 psi. I then used a heat gun to heat the TXV and the low side pressure would drop to about 68 psi and then slowly rise to 75 psi when heat was removed. High side would creep up to about 85 psi and hold steady. The engine cooling fans never cut on and engine temp held steady at 210 degrees. Outside air temp is approx. 60 degrees.

Edited April 9, 2023 by Air2Air

[MikeBMW]

Please keep us updated. In my experience it usually comes down the condenser ahead of the radiator.
At least, for a number of friends. Fortunately, I have yet to experience this - their trucks were also a 2014 model.

[mikeyk101]

Those codes point to a possible ground issue that can cause a multitude of problems, possibly the cooling issue you are having as long as your evaporator is not leaking. And 2014-15 were famous for the g218 ground issue. It is a ground that can be accessed under left top dash speaker. There was a problem during manufacturing where part of the insulation didn't let the ground get full contact. Removing the bolt, cutting the insulation away so a better ground is achieved and putting bolt back on can fix this. There are other possible ground/power  issues that are worth checking out. Take a look at this pdf of the service bulletin:

 

https://static.nhtsa.gov/odi/tsbs/2022/MC-10209138-0001.pdf

[mikeyk101]

Here is a YouTube video that will help in checking the G218 and there is another similar ground behind right top dash speaker as well. After watching the fix, fast forward to 9:20 to see what the problem may look like before the fix.