Ok this summer got the AC charged. It never really blew cold air. Yesterday took it out and it won’t blow heat. The fan is working. Where can I look to see if the door is opening. And find the reason why it isn’t.

Thanks.

It is possible the lever that controls heat/cool air is broken. Empty out your glove box. Disconnect the cable that holds it open and allow the glove box door to open all the way and hang down. In the back, there is a lever on the top of the HVAC unit attached to a cable. The other end of the cable is attached to the sliding lever in your dash that goes from cool to heat. If the lever on top of the HVAC unit is broke then the HVAC door will not move when you move the slide back and forth. Mine was broke. I found a new one on GBodyParts.com

Good Luck

check this tech article: www.montecarloss.com/SS_FAQ_16.html#4 and see if it helps and good luck!!

Ok this is a long shot. I did what you said. Yes the cable wasn’t hooked up. Well the tab that it hooks to is broken off. How do I fix that? Thanks

You need to buy this.
https://www.mikesmontes.com/Air-Distribution-Door-Control-Lever_p_2703.html

And insure that the cable's plastic end is also not broken.
https://www.mikesmontes.com/AC-Heater-Control-Cable_p_3123.html

A few months ago replaced both. Thought it was just a lever to replace but then had to again order a cable as the plastic on the lever side was not secure to the housing, broke, and in turn broke the lever.
Check that the cable is good. It is a PITA to replace the cable, attachment to the A/C control requires finesse and removal out of dash.
Bob

What Bob said above and good luck!!

I am sure the cable is good. It moves back and forth. I am wondering how that control lever comes out.

It's in the link I provided!!

Is the bellcrank broke off at the housing? Looking at the picture of the bellcrank on Mike's website it is shown upside down, The "T" actually points down and is inserted into the housing, it's is the pivot for the bellcrank, and also when inserted into a slot and turned prevents the bellcrank from coming out . The T is what prevents the bellcrank from releasing from the housing while the bellcrank is opening and closing the heater door.
The broken T needs to be turned to align it back to the slot to remove it.

My bellcrank was broke at the "shaft" of the T. And that shaft points up and only protrudes from the housing a little. The tool I finally found to remove the broken T was an alligator clip. Like this:
https://www.tequipment.net/Mueller-Electric/BU-60X/Alligator-Clips/

the sharp teeth bit into the plastic so I could pick the T up and then rebite it so I had a good hold on it. Then you need to turn the broken T to realign it with the slot while pull light tension upward.
It's a trial and error pick and pull up.
A PITA in a small limited space.
A flashlight and an inspection mirror and you can look down into the area you need to work at.

Put a drop of lithium grease on the bellcrank pivot before installing the new one.

Adjusting the stroke on the cable. You want that heater door the cable moves to be able to close fully in the "heater off" position. Heat on position much, much, less to worry about. In the summer time that door need to be as close to 100% closed for A/C to work well. When you slide the "heat" control to the left COLD, it will not touch the end of the slot, just short.
Bob

I said the same thing in my tech FAQ!!