Have a 1999 suburban with the dual zone heat/ac. Rear zone is working just fine. Front zone not working at all (no heat, no cold, no floor vent/defrost etc...). Have checked all fuses/relays/etc...

There is a distinct click or knocking noise that happens when the selector **** is turned from medium-high to high when the car is on. Left the **** at high for a few seconds and smoke that smelled like burning plastic came out of the defrost vent (the setting it was on). Any ideas?

Thanks in advance.

 

Welcome to the forum.

Is the blower working?

 

I am having a similar issue however, I believe it is the air door actuator. I have read many threads but no luck at finding info for a 2000 Suburban. Is it behind the glove compartment and will I need to take the dash out? (I am a girl with small hands) I need to get this figured out ASAP, I am a cold blooded girl and this 'kinda' warm just isn't cutting it!

Thanks for your hlep!!!

Cargirl

 

Welcome to the forum. Sure seems to be a lot of folks w/ HVAC issues this winter. Someone here can probably lend a hand.

 

If you lay on the floor and reach up behind the dash almost directly above the gas pedal, there is an actuated flap there. If you move the duct selector, see if you can feel movement. There is a spring on this that can come off or the plastic it attaches to can be broken. If you have small hands that you don't mind getting scratched, I think this is where it is.

 

I think this picture might help.