A/C question on the 99 Tahoe

[07Burb]

my AC is not cold and I’m not sure why. It was cold until about 3 weeks ago and I’m not sure what’s happened. I’ve top off the r134a. That didn’t work. I replaced the climate control switch. That didn’t fix the air temp issue (needed replaced anyway). I have also replaced the actuator that controls the temperature. That didn’t fix it either.

Any other ideas? I’ve double checked the R134 pressure and it’s staying at the desired level so there’s not a big leak somewhere

EDIT: I’ve also confirmed that the compressor is engaging and appears to be working

 

[fastpat]

At this point I'd consider a reliable HVAC shop, unless you want to spend more time on this. Are all your vacuum hoses fresh? Other actuators functional?

Based on your posts I've read, I know you're a knowledgeable man, so we both know that the HVAC isn't a mystery, just ornery sometimes.

 

[YAMBAG]

Did you check the pressure on both the low AND hi side? Just checking the low side isnt good enough.

 

[sumo]

Yes I’d check the pressure sensor. Jump the low side and see if that works. If so faulty sensor

 

[YAMBAG]

Couple more things Id like to add.

check the heater core and the box and look for debris buildup on the core. There are youtube videos on how to clean it out.

Check the condenser for debris. Clean with pressurized water and a cleaning solution

also check the high and low pressure (PSI) of the system and ensure it is running as efficient as possible. These trucks take 2lbs of R134. DO NOT overfill it.