Air conditioner and heater only working on one side?

Okay, then I am concerned. Heat should be coming from both sides.

It may either be a clogged heater core or low coolant level.

Check the coolant level and be sure it is full.

If it is, you need to flush the heater core. Remove both hoses from the core and use a garden hose and run it through the pipes back and forth until you get all the debris out and get an even flow of water out of the pipes.

Roy

You are welcome.

Keep us updated.

Roy

First I recommend a scan with GM scantool to retrieve fault codes, but you can try this if you want.
AIR MIX VALVE 1. Remove glove box. Start engine. Set temperature control to 90 °F (32 °C). Set passenger control panel to full WARM position. If ambient temperature is greater than 90 °F (32 °C), disconnect in-vehicle temperature sensor. Allow at least 45 seconds for programmer output cranks to reach full heating position. 2. Gently pull driver air mix valve crank toward programmer until valve contacts stop. Insert threaded portion of link into slot on plastic pin on driver air mix valve crank. 3. Gently pull passenger air mix valve crank toward actuator until valve contacts stop. Insert threaded portion of link into slot on plastic pin on passenger air mix valve crank. See Fig. 1 .

I would start with the actuator that is groaning and moving around on its own. It may be shorted internally, that is why it keeps moving back and forth. They should all go to where they are told, and stay there, not move back and forth

I would check to see if the blend door actuator is bad. If it is vacuum then try to find the door actuator and move them manually to see if you can find the issue.

Hi,

Does it change from floor to defroster? I attached a pic below. There are two mode door actuators. One is for the AC/defrost. It is number 9 in the pic. Number 8 is the mode door actuator. Let me know if you are able to change air flow directions to any of the other locations. If it is only A/C and the panels, check for a vacuum supply to actuator #9.

Let me know.

Joe

Okay, everything is at the floor. I need you to check for vacuum to the two actuators in the above pic. Do this with the engine running and let me know what you find.

Joe

The lack of engine vacuum is the cause. Confirm there is vacuum at the supply (the pic above). If there is, then you have a leak between the two locations. Often times with the engine at an idle, you can hear a hissing sound. Also, the plastic vacuum hose they used is commonly known to break.

So, behind the dash on the selector control head, check for vacuum from the engine and make sure nothing is cracked or damaged there. I attached a pic of the vacuum schematic on the rear of that unit.

Let me know what you find.

Joe

Hi,

I believe that's it. Is there vacuum to the lines in pic 3? If there isn't, follow it to the engine intake manifold and see if there is a break.

Joe