What have the 3 different places tested? What have they told you about it?

 

Basically nothing, they throw gauges on it say the levels look good and "trouble shoot it" with no answers. One place told me he thinks it's a electrical issue but wasn't able figure it out. I did run some tests myself and I did notice I have a few sensors reading negative degrees but haven't been able to dig up any information on them. I attached two pics

 

Spring for a subscription on Alldatadiy.com for your truck. It's a full factory manual with all the specs you'll need. This is what they have for my '11 Tahoe.

 

Thank you

 

Just to be clear.
If I use a jumper wire on the cycling switch connector the compressor will engage"

Just trying to backtrack and see if my comp. clutch will engage.

 

If jumping low pressure cutoff makes it work and system is fully charged then yes cutoff is bad. I had a intermittent one on my old Malibu, they have a valve under them so easy to swap out.

 

Just an update.
I replaced my leaking radiator so that's out of the way.

While I had it apart I checked all the AC connectors. I unplugged them, twisted, and wiggled them.
I removed and double checked the orifice tube and removed and manipulated the low schrader valve.
Made sure nothing was clogging the condenser. I did pull a small dead bird out.
Took the truck over and evacuated the system again.
Low and behold...It took all 2.8 lbs of freon. No issues. Turned on AC. Compressor engaged. Fans came on. Cold air!

Why it wouldn't take freon before?..I don't know. Only thing I can think of is the schrader locked up somehow?

Going to keep an eye on the electric fans. I think that may be where my problems originated from.

 

UPDATE: So....it's Sept. 8, 2022.....and I still have the issue. Two summers of this...
The refrigerant is full. Low & high pressure sensors new, Disconnected ECT connector and fans come on full speed.
I got through the last part of summer 2020 by putting in a toggle switch to manually provide 12v to the compressor and it works great.
I just have to turn off the toggle while sitting at a stop or the compressor will start to chatter due to high pressure build up?

Dropped it at a another shop to have it looked at.....no answer...again Maybe? a bad PCM.
I went ahead and ordered a PCM and it will be here in a couple of weeks. I'll have it installed and we shall see.

In the meantime, to finish out this summer, the fans have been wired to come on when I turn on the AC toggle.
That should keep the pressures from building when stopped.
A stop gap for a couple of weeks, I hope.

 

So the two switches hi/lo go to the body control module. bcm sends a ground to the compressor relay to engage. Comp relay should have hot on one side with key on at all times. Light blue wire on the back of the control head sends signal to the bcm requesting ac.

I have hot wired several. Take a ground and run it through a toggle switch on the dash. Next run that wire in series through both hi and lo switches, no longer leaving them connected to the bcm, then apply it to the comp relay gd to run it. This removes the protection of if the vehicle overheats, or whatever, it disables the ac, but it does work. You would have control over running the ac with a switch on the dash and the hi and lo switches will protect the system as normal.

 

UPDATE: Oct. 27, 2022.
Dropped off the burb at a shop.

Had the PCM replaced with one from company Flagship One. The shop replaced the HVAC control on the dash. Spent a few $$$$
Drove home agitated. Same issue. No AC. Not cycling.

Took it back today, a week later.
Evac system and refill. It was low maybe less than 1/4 lb of freon. Same issue. No AC. Not cycling
Changed the pressure sensors that I already replaced. Same issue. No AC Not cycling

Had to leave it overnight and they are going to check it out tomorrow. The mechanic doesn't know why it isn't working.
This is exactly why I took it to a shop because I already did everything they did and thought I needed a more experienced mechanic....I guess I was wrong.