Hello, thanks for the add. I have a 2003 Hummer H2. I'm needing some help and I was wondering if anyone has run into this same issue I am having. I will try to be as clear as I can with the details. So when its around 100 outside my ac can't keep up. I mean my air flow when my ac is on high is very very weak. My kids are sweating in the back seat while I'm cool up front. I have pointed all the vents towards the rear of the hummer but nothing helps. Here is a list of things we have done, cleaned, or replaced.

1st --we changed the fan clutch and put a 160 thermostat in the water pump.
2nd-- we recharged the ac. We put in all new refrigerant and replaced the low side valve to ensure it's not leaking etc.
3rd --we got a brand new blower motor and resistor.
4th-- this was the Big job. pulled the dash and heater box to inspect the ac evaporator to see if it was dirty. And it was! So we cleaned and degreased it to move to dirt off it. As soon as this was pulled out we thought that was our issue all along. Sadly, we were wrong. Yes, the air does blow a little harder but still not like my 03 Tahoe. It's like its on middle compared to the Tahoe.
5th-- we replaced the ac controller. Same results.
6th-- we checked the blend door actuator motors all seem to be working as they should. We don't have a scan tool so we did this visually and all were moving etc.

My compressor clutch fan is engaging and working correctly. We are at a loss here. Please any help or if anyone has ran into this issue and has the fix we would love to hear it. I don't want to sell my car, but if the ac cant keep my car cool I'm going to have too :-( While the dash was out we check all the vents all are clean and clear of trash etc. I use the recirculation button ( From the looks of the Evp the old owner did not.)

 

I MOVED this to the H2 section, where questions about H2s go. The Forums Help & Suggestion Center is for questions about how to use the forums and has nothing to do with any vehicle (like: How do I post a picture?).

I am not familiar with the H2 AC system specifically, but someone will come along to help.

As for AC in GM trucks, first thing I would have done is clean the Condenser and Radiator.

When you put in a cooler T Stat you reduce AC efficiency because you shift heat into the cooling system (Radiator) and out of the engine. The Condenser is directly in front of the Radiator, increasing its heat as well. I would never have done that to try to help with AC.

Good luck.

 

With the airflow being "weak" I can only think that either some of the ductwork under the dash has come loose or leaking, one of the blend doors is malfunctioning, or the new blower motor is not up to par.

On your Tahoe - does it have the standard AC controls or the "automatic" ones like the Hummer? That could be some of the difference. I know on the standard AC things are far more basic versus the digital automatic setups.

The replacement blower motor - did you get a genuine AC Delco one or some other brand? Quite possible if another brand its just inferior or could just be defective.

The clutch fan, compressor, refrigerant, etc will have zero affect on how hard it blows inside, just the temperature of the air obviously.

Another thing that can change how inside temps are perceived are if one vehicle has factory (or aftermarket) tinted glass as well as the color of the paint job. A white vehicle will stay a bit cooler than a dark blue one for example. Just throwing some ideas and things out here.

Aside from the airflow inside, if it struggles to maintain temps at speeds under about 30 mph then you could look at having a quality electric fans installed on the front of the condenser that is relay triggered with the AC compressor.