Heat stuck on 1999 Jimmy SLT- hot in Atlanta

[A Atlanta]

I own a 1999 SLT with 90,000 miles. The heater is stuck on regardless of the temp setting. The blower works. I can control the air flow (floor, panel and defrost), but only hot air. I have heard a clicking and thumping noise in the dash behind the glove compartment. I think it is an issue with the blend door. What am I looking at to repair?

[old_master]

There is an electric actuator that operates the temperature blend door. It has a plastic drive gear that commonly breaks. I haven't had the opportunity or the pleasure to do it myself, but I understand they can be repaired rather easily, once you get to it.

[A Atlanta]

How do I get to it?

[old_master]

The temperature blend door actuator is mounted to the outside of the heater case. I'm not sure if you can access the actuator without complete dash removal. It might be possible to access it by removing the glove box, it's located directly behind it.