I did searches and didn't find anything that really satisfied my itch.

AC is properly charged. I do not have auto temp control. Heat works fine. Compressor does not "short" cycle as if refrigerant is low.

Ok, AC can either be in AC postition (normal) or bi-level and I get 57-62 discharge air temp. I can turn the **** to MAX position and the temp drops to the mid 40s on discharge.

Could the temp door be cracking open? Is it controlled by vacuum or electric motor? Any sensors I need to check?

Temp **** is turned all the way counterclockwise to coldest position.

2002 2 dr, ZR2 Blazer, auto, 4WD, 90k miles

 

What is the outside temp and inside temp when you are doing this test? When on MAX, the fan pulls air from inside the cabin. When not on MAX, it pulls from the cowl area outside of the truck.

These do not sound all that bad as far as temperatures, especially if sitting still with a fully warmed up vehicle.

 

I was curious before I messed with it. I've done a few ac in my life and this one seemed a little strange. I've gotten the DAT a lot lower on other vehicles in very similar conditions. To me the ac should be putting out better on bi-level and normal settings. That's what makes me wonder about the temp door, if it was somehow maybe modulating a little. Does the temp door work off of vacuum or elctric motor? Thanks.

 

Electric.

It comes down to interior vs exterior temperatures. As I said, the AC system pulls in outside air on any mode except MAX AC. If it is cooler inside, then the DAT will be cooler.

 

As stated, the exterior temp could cause the readings that you're seeing since they're not out of the ordinary.
Make certain that the clutch in the cooling fan (behind the radiator) is working correctly. If the discharge temps are significantly lower when under way, you may have a defective fan clutch. I lost one pick-up truck to a defective fan clutch (blown head gasket) so it's not a trivial problem.
Also, raising the engine speed at curb side will greatly affect the A/C performance. Try it too.

 

Hey guys, THANKS for your responses! This just gives me some avenues to explore to make sure everything is on the "Up & Up". Didn't mean to kinda sound like a broken record on some things. I'm new to a Blazer but lots of experience on Z28s and stuff. Sold my 95 Z (special order and only owner for almost 14 years) to get a ZR2. Something different. Anything I can do to help a member here, just ask. If you're close, shoot, come on by. 24572