My heater was working one day and then it just quit working on me. When I turn the control to heat it sounds like its going to blow heat out but never does. Also my a/c control with the defrost and vent adjustments doesn't work at all it can only turn my air on and off and nothing else. If there is anyone who can help me please let me know. Thanks

 

Id check to see what your antifreeze level is. I had a similar problem. I head a leaking heater core wich im in the midst of replacing

 

If you can not change the mode (defrost, floor, front panel, bi-level), then I'm betting that the vacuum source to the HVAC control head has either been disconnected or otherwise interupted.

Is this a 4wd truck?

 

No its a 2000 2wd s-10 blazer.

 

That simplifies things a bit more.

There is a vacuum reservoir in the driver's side fender that stores vacuum pressure for the HVAC system. I would make sure that the vacuum supply is still connected to the engine. Follow the hoses from the res to the engine as well as what goes into the firewall to the HVAC control head in the dash.

 

what about the blower motor? i have the same problem in my truck and what ive been hearing is the blower motor died.