HVAC actuator issue under dash

[Miranthis]

I searched and can't find this on the forum, so I am asking.

My HVAC unit in the 2008 SR5 has been making a noise, like a door actuator or gear is going bad. It recently got worse. I cannot find what part of the Service Manual handles the R&R on the dash and the HVAC unit. Having the PDF version is not convenient for browsing. Anyone know what part of the manual deals with this system?


Jeff

 

[Miranthis]

found some reference to the AC Amplifier (that appears to be on the drivers side of the ceterline), but I think mine is an issue with the servo that changes the air from defrost to face to feet (which is on the passenger side of the cerline betweent he avaporator and the blower motor assembly) . It is making a loud buzzing when I call for face air, and it is clicking, like it can't get into the right positon or is slipping a tooth, when I need the mix of face and feet.

Gonna take out the glove box and see what I can see...

 

[Syr4RinNC]

Yea, the AC amplifier/ HVAC ECU is just a computer chip. You want the blend door actuator/ servo assay

DIY: Replace Servo Sub-Assy

 

[Miranthis]

I checked the servos and onlyu one was buzzing, and it was the upper one, not the blend door actuator. It was the HVAC Air Inlet Door Actuator (87106-35120). So i pulled it to see if I could clean it or if it was really broken. That required first turning ON the recirc button so the recirc door actuates out of the way. Then removing the glove box (one screw on the closer and them pull) and the black upper box (4 mounting screws).

The next step is removing two of three screws on the metal bracket that holds the servo box (becasue the third is burried so deep ther eis no hope of reachign it without dash disassembly�&#56879 . Then i could manuever (bend carefully) the metal frame to access three small screws that hold the servo to the metal frame (top two are EASY, bottom rear one is a *****). Also helps to decouple the blue wire loom from the bracket. When those are all out, the servor and arttached white gear can be manuvered out.

I opened the case and cleaned out all the old, hard lithium grease on the gears. The contact plate for the electronics was gummed up with old, haer dielectric grease andthe contact forks were not making contact. Cleaned it all and reassembled.

Now it works fine, no noise, and smooth... Just got dirty and gummed up.