Intermittent A/C Cooling Problem

[amrg]

The A/C is cooling intermittently and I don't know whats wrong. Its cold one minute, and suddenly not cooling, then cold again. I've got the thermo set on maximum cooling. The problem is with the Alpha, the I5 never did this at all. Anyone know what could be the issue here?

 

[ArtHummer]

When was the last time you serviced the AC system? Maybe you have a small AC leak. If the pressure will drop to low it will not have any cooling effect.

 

[amrg]

I took the truck to the dealer and complained about the problem 3 weeks ago. The service rep noted it down as A/C not cooling. I received the truck a week later and the problem should've been fixed. If there was a leak, I shouldn't be getting any cooling at all. In my case its cooling one sec then not so the next....

 

[amrg]

Bumping this.

I took the truck to the dealer and kept it there for 5 days. They presumably tested everything. The issue is still there. Now I can tell that it only happens while driving, Im not sure exactly how, but I noticed if I do a hard acceleration in 1st gear and then let off and the truck switches to second, the cooling just dies. What am I missing here?!!!

 

[ArtHummer]

Maybe a bad clutch on your AC compressor. When engine drops the RPMs the clutch is disengaging.

 

[Steve #1]

Check all the wiring on the back of the AC controls. May not be the problem but cheep and easy.

Under hard acceleration, the AC clutch should disengage, but should re engage when you let off.

 

[Sethmark]

I'm betting you get a pretty big puddle under the car when you park? It's programmed into the ac to turn off at certain intervals to allow the core to defrost. Could be you're getting a lot of humidity?

 

[3rdH3]

Bumping this.

I took the truck to the dealer and kept it there for 5 days. They presumably tested everything. The issue is still there. Now I can tell that it only happens while driving, Im not sure exactly how, but I noticed if I do a hard acceleration in 1st gear and then let off and the truck switches to second, the cooling just dies. What am I missing here?!!!

Some vehicles have an AC cutoff switch for when you are under hard acceleration. I don't know about the Alpha's. I haven't noticed it on mine but then again I drive like an old lady.

 

[amrg]

I'm betting you get a pretty big puddle under the car when you park? It's programmed into the ac to turn off at certain intervals to allow the core to defrost. Could be you're getting a lot of humidity?

I really have no clue wtf is going on. I do feel humidity inside the cabin. The cooling as i said sometimes gets almost to zero, and sometimes its just humid. Im extremely confused and the fact the dealer is unable to get to anything is frustrating.
A friend of mine that works on Jeeps told me that they have a device inside the cabin that allows to direct heat away from the radiator to the inside of the cabin (idea to why to switch the blower on max with thermos on extreme heat to cool down the engine at extreme situations). Could that be my issue there?
As for if a bad clutch issue, any way to diagnose that?

 

[Steve #1]

Try swapping the controls from your other H3.

 

[ArtHummer]

... As for if a bad clutch issue, any way to diagnose that?

If you look at the AC Compressor pulley, the front part of it is a clutch and where the belt sits is the free spinning pulley. Now is the AC is not not on, you will notice that pulley is spinning but the clutch is not (it would stay still). When AC is on, the clutch will push on the pulley and will spine at the same rate and speed as the pulley... Now what you need to do is to drive your truck until you will fell the symptoms that AC is not working, park it and look if the clutch is spinning. Also make sure that it spines at the same speed as pulley and is not making any grinding noise.

 

[Sethmark]

Here's something to try.... Run the ac on recirculate and see if it helps the problem. This accomplishes 2 things. First, it makes the air in the car colder and it dries it out more. I bet your problem goes away as long as its recirculating.

 

[Hans3T]

You can try recalibrating the system.

Important: Do not adjust any controls on the HVAC control assembly during self-calibration. If interrupted, improper HVAC performance will result.

•Turn ON the ignition with the engine OFF.
•Turn the Temperature dial all the way to the right.
•Turn the blower control dial all the way to the right.
•Turn the mode position dial all the way to the left.
•Simultaneously press and hold the A/C and Defrost buttons until the LED's start to flash.
•Once the LED's stop flashing, calibration is complete

Sent with Tapacrack

 

[JGBB04]

maybe the high pressure switch, haven't had an issue w/ the T but my old explorer went through a couple of them.

 

[amrg]

maybe the high pressure switch, haven't had an issue w/ the T but my old explorer went through a couple of them.

What exactly is that switch?
And what does the re calibration achieve ? Ill try it though

 

[JGBB04]

What exactly is that switch?

The pdf files are too big to upload in post, pm me your email & I'll send them to you. From the manual "The A/C refrigerant pressure sensor protects the A/C system from operating when an excessively
high or low pressure condition exists. The powertrain control module (PCM) disables the
compressor clutch under the following conditions: A/C pressure is more than 2,951 kPa (428 psi). The clutch will be enabled after the pressure
decreases to less than 2,068 kPa (300 psi). A/C high side pressure is less than 310 kPa (44 psi).
The clutch will be enabled after the A/C high side pressure increases to more than 310 kPa (44
psi)."

 

[alrock]

The calibration procedure recalibrates the temperature control doors and the direction doors (defrost to dash vents to floor). When you do it you can here the doors opening and closing and the air moving across the various vents.

 

[escamim]

Hey bro, could you please send me the a/c manual (hummer H3)?
Thanks in advance

Escamim@gmail.com