HVAC/AC issues

[Fuzzy]

I've got a few problems with the HVAC in my truck, first of all I have no control over the vents, I just get air out of the Defrost and Upper vents, I tried replacing my HVAC controller with a salvage yard unit and nothing changed so I'm assuming it's not as simple as that. I can hear something trying to actuate under the dash if I switch the vent direction but its unable to switch.

Second is an AC leak somewhere, I put some R134 in and it leaked out as expected within about two weeks, while the system had refrigerant the compressor worked fine so I know that's not the issue, and I did have cool ac. I've remember reading about the orifice tube being a common leak on these trucks, whats the best way to check it? Also are there any other common AC system problems on these trucks.

 

[someotherguy]

Common:

Really common for the 1995-up controllers to be bad; the one you got from the boneyard could very easily be bad, too.

Really common for the 1996-up compressors (HT6) to leak around the middle of the case. Check for oily/dirty residue.

Richard

 

[Fuzzy]

Yeah, I'm guessing that the scrap unit is worse than the one I've got because the lights are out in it and the recirc button doesnt work.

I'll take a look at the compressor, but I haven't noticed any oil or damp spots on it any other time I've looked at it, but I've never looked in a particular spot on it.

 

[thunderstruck]

Before you condemn your controller, make sure the large plastic gear inside your blend door actuator isn't cracked. It's very easy to remove that particular actuator. It's held on by two screws beneath the dash to the right of the accelerator pedal.


Sent from my Nintendo 64

 

[Dr.Zoom]

^^ That's what I was thinking. If you hear the actuator trying to work, then your controls are doing something.

 

[Dr.Zoom]

While you have the actuator off, work the vents manually to make sure the mechanism is not stuck. My actuator was missing when I bought my suburban. The new one was misaligned when I installed it. I don't remember how I got everything back in sync. I think disconnecting the battery, but I don't recall for sure.

 

[Fuzzy]

I looked at the mode actuator, and I believe that's bad, so I'll replace that soon.

I also looked at the compressor and aside for the grime that covers it and everything else in the engine bay I didn't notice any damp/oily spots, so I don't think that's bad.