Fresh Air Damper Motor

[icanfixit]

'94 GMC Z71 4x4

 

I have a fresh air damper motor that is making loud clicking/clacking noise at start up and shut down. The damper does move but makes a heck of a racket. Kinda like a gear drive is 'snapping' past it's gears.

 

I have the three bolts removed on the firewall under the anti freeze resi and the four screws that fasten the blower housing to the rest of the air box under the dash. How do you slide it out to get at the damper moter? It seems like something else is holding in place. It does move around but wil not drop down to snake it out from under the dash.

 

Does anyone have a precedure on how to replace the damper motor that would help me out?

[Zembonez]

It isn't going to slide out without disconnecting the AC lines and heater hoses... BUT... I've never seen a housing that you had to remove from the vehicle to work on. The air mix motors are most always on the outside of the case under the dash. You guys can correct me if I am wrong...

[icanfixit]

You are correct if you are removing the entire Air Box Assembly. (which I have done on my '88 years ago chasing a leak) And you are correct that the other damper motors, Mode & Temp are easier to get at.

 

What I need to get at is the damper motor for the fresh air damper. It changes position depending on if you want fresh air or to re-circulate cabin air way up front under the passenger side dash. Mine moves at startup, shut down & MAX A/C.

 

It's mounted on the "blower housing" inlet side, on the backside closer to the firewall. The "blower housing" is attached, (glued?), to a rectangular box which is between the blower inlet & the firewall. The box goes up and pulls outside air from either the passenger side front fender or just in front of the passenger windshield. (Not sure which).

 

The discharge of the blower housing is attached to the rest of the "Air Box" with four screws. When these screws are removed you can see the A/C Evaporator.

 

I have all the screws/bolts I can find removed but it feels like ther is a clip or indexing pin that is holding things up. IT moves around but does not drop down. Moves left and right about 1/4" right now. From whqt I can see I might need to remove the firewall electrical plug that is right there to give me more free area to work with.

[Mike G]

I have no answers for you, but is this the unit I have heard referred to as the "blend door motor" as well? If you get it figured out, let me know your processes as mine has been beating itself up for about three years now...

--Mike