The air coming out the right front vents is cold; but, the air coming out the left front vents (driver's side) is warm. Sliding left ac slider switch up and down did no good. Considered fuse, but both left and right AC controls run through same fuse. Suspect bad motor for left side plenum duct, or bad connection, or faulty vacuum at motor (if motor is vacuum actuated). Considering removing dash cover to see if I can find the motor, but not sure how to remove dash cover, or even if that's the way to find the motor.

Any suggestions will be appreciated.

mine does the same thing. it gets low on refrigerant (a slow leak somewhere) and for some reason the driver gets shafted. all you have to do is top it off with a can or so.
there is another thread somewhere in this forum where someone had the same problem and topping off the refrigerant also worked for them. try that before spending tons of $$$ on other stuff.

Thanks adoublearonn. You were right. I put in some freon, and now it's blowing real cold!

Just in case someone else reads this, here are a few things I learned doing this:
1. Wal-Mart sells R134a. I bought a can that came with a pressure gauge already attached for $20. I wanted the gauge so I could tell if the pressure was in the green zone on the gauge, which the gauge says means to add refrigerant.
2. It took me awhile to find the low pressure fitting. Initially I found a fitting on the drivers side with a black cap which I tried to connect the R134 fitting to. But it was too big. I still don't know what that fitting is for. Maybe it's the high pressure fitting. It doesn't have any threads on it. Anyway, I finally found the low pressure fitting at the rear of the engine, right in the middle, near the firewall. It's a treaded fitting about 7/16 inch in diameter.
3. When I connected the R134 fitting and checked the pressure it read about 30, and was in the blue zone on the gauge. The blue zone says its already charged. But, since the left vents were blowing warm, I decided to go ahead and add freon. After adding the 15 ounces of freon the gauge went up to 35, still in the blue zone. And, the left vents are now blowing cold. So, I guess I did this right.

Just wanted to say thanks for this post. My monte was doing the same thing. I had just recently bought it so I took it back before actually finalizing everything. He had some ideas so I let him try what he thought, when it didn't work I told him what I had read on here. He figured what the heck, I'll give it a try and it worked!!! Air is ice cold now! Thanks for the information.