Hey whats up guys I have a question my brother has a 94 GMC Serria pickup
and for some reason every time he starts it or turns it off you get tap tap tap over and over it stop after like 20 taps but it iscoming from the passenger side under the dash right next to the kicker panel, I was told that it might be the blend door on the ACany Ideas they would be appreciated. Oh and thanks inAdvance!

 

It is the fresh-air door actuator...it needs replacing

 

You wouldnt happen to know were that was located would if not thats cool???

 

yes...by the passenger kick panel..sort of wedged between the a/xc case and the blower fan...obne screw is easy,one is a bitch

 

I have a 2001 Siera and have replaced the modulator control in the dash and have also replaced the blend door actuator under the dash over the hump. My problem is that when I turn the heat on and then return to the cool settingthe actuator will not return to the cool position. However after the truck has sat for a while it will return to the cool position. Any ideras
Thanks Greg

 

on both sides...or 1 side??

 

What do you mean? Are there 2 actuators
Thanks greg

 

These trucks have 4 actuators...
The lower one (acessible) is ONLY for the drivers' side temp....there is an upper one you can't get to for the passenger temp....a recirc one....and a mode one that directs the airflow

 

Argon, Thanks for all the info. WhenI have the Blend door actuator (the one on the hump below the dash), and I have it pluged in and just hanging loose, I turn the heat dial and I can visualize the motor turning to what ever position I have set. When I turn the dial back counter clock wise to cool it gets hung up and sticks at the point that I had set initially set on the temp dial. If I leave it alone for a while it will return to the cool position. Could it be the wire harness?
Thanks for all your help
Greg

 

for ****s n giggles....

go to the passenger side and open the door...remove the end panel piece,revealing some plugs and sduch...

a big,brownish plug..make SURE its pushed in all the way...then check the others