2003 Sierra Air Conditioning Problems

[TexasSierra]

Hey everyone, I had a couple questions...

 

Backstory, I just bought a 2003 GMC Sierra 1500 Z71 and have an issue with the AC, which I'd like to get fixed because it's 105 degrees right now in Houston.

 

When I turn on the AC in the truck, no matter what I select, no matter what buttons I push or temperature I select, very little, if anything, comes out of any of the four vents in the dash, but the defrost vent blows full blast. The air coming out of the defrost vent isn't hot, but it's not exactly cold either.

 

I tried the trick of pulling the fuse and letting the AC recalibrate itself, but that didn't do anything. I put refrigerant in it, that didn't do anything either.

 

Aside from taking it to the shop, is there anything specific that I should be looking for? I really don't want to have to pull the dash apart. If the compressor is bad, would that prevent air from blowing out of the vents and only the defrost? I've read that it could possibly be a leak from vacuum lines? Though I had a vehicle inspector/mechanic argue with me that these trucks didn't have vacuum lines for the air vents (no clue one way or another.) Could it be a bad blower motor or bad blower motor resistor that's causing it?

 

I appreciate any and all answers.

 

[txab]

The actuators are electric and are prone to going bad.

 

You could have a blend door actuator bad and your mixing hot air with the cold from AC

You could be low on charge or even overcharged since you added.

You could have weak compressor or clutch. you may have a leak elsewhere in the system requiring repair, vacuuming the system and then recharging

 

Since apparently you know nothing about the operation of a refrigerant system and probably don't have a set of gauges to read hi & lo sides of the sytem, I suggest you take it to a professional.

 

The actuators you can replace a couple of them aren't too bad, others are pretty time consuming to get to.

 

I'd work the actuator problem first. Find where you can get a set of AC service gauges so you can monitor both sides of system

[richard wysong]

I agree with Txab, does the compressor even turn on? they aren't the easiest compressors to see, it also uses a seperate belt that is hard to see if it's even there. your blower works so it's not the resistor. There are no vacuum lines it's all electrc actuators and I'm not sure if there is a seperate fuse for them

[stu_pidasso]

Could have a dumpy belt that cant turn the compressor hard enough. Check that guy out too. 

[TexasSierra]

I'm sorry for the delayed response, I got wrapped up in work and getting my kids ready to go back to school. I appreciate the responses. I found a video on Youtube that showed how to remove the actuator under the drivers side dash and removed it, it's blowing great now.

 

I have another problem that's kinda weird to me, but I'm sure it's because I'm as dumb as a fence post when it comes to the operation of a refrigerant system. I haven't really driven the truck much because there's some work I need to do and get done to it, but when I fire it up and let it run a bit, the AC had been blowing hot.

 

Today, I fired it up, it was blowing hot, so I turned it off. When I went to turn it back on, the button wasn't working, so I hit "auto" and it came on and was blowing ice cold.

 

I don't really know what to make of it, any ideas?

Edited July 31, 2022 by TexasSierra

[richard wysong]

probablythe actuator for the blend door was stuck or on its way out as well