1999 Blazer se. I have tried a search and couldn't find an answer to my specific question. I have back flushed my heater core three times and the actuater motor seams to working fine, I popped out the glove box and can see the lever moving to the different positions. but still no heat. My question is - Is there a relay of some kind for the temperature control ****? When I turn the **** to hot or cold, there is not the remotest change in temperature. It would seem that even with a severly clogged core, there would be some small change in temperature but I get nothing, nothing, nothing! Thanks in advance.

 

You cannot see the movement of the temp door. The temp door actuator is electronic and is not vacuum operated like the other doors. It is located on top of the HVAC housing behind the glove box almost directly under the dash speaker.

 

OK thank you! Is there a relay or something I can get to first or do I dig right in and go directly to the temp door.