A/c Weird Problem

[mjbret13]

A/c works fine, vents will change between the modes just fine, ex. Max works fine, heat works, defrost, bi level, and vent. But no mater the setting it seems like the defrost never shuts off. I'm stumped on how to fix this problem. It all worked fine till recently.

[ftpiercecracker1]

Vacuum is what controls the 'flappers' that divert the air to where ever you want it to go. So, either A. something has gummed up the works and you defrost 'flapper' won't close all the way or B. one of the vacuum lines has a break in it. All it takes is a pinhole for the vacuum to be lost.

 

FYI when you do lose vacuum, defrost is the default position.

 

 

Its sounds pretty simple to me, since everything else works you obviously still have vacuum. Its probably just a piece of garbage stuck in there somewhere.

 

 

Maybe, don't fix what aint broke? :dunno:

[mjbret13]

Most of the cold air goes towards the windshield when it should be at me and my passenger. That's the part that bugs me. Otherwise it handles the heat waves fine.

[sloride]

Sounds like your defrost door actuator has become faulty or its not getting full vacuum.

 

With the vehicle running, look up under the dash and watch to see if the actuator arm moves when you cycle thru the a/c-heater control on dash.  The arm is a two piece design and will 'scissor' up and down.  You'll need to take the lower dash valence off to see up there.  Break out your mirror and a good flashlight, it will be on the drivers side of the heater box.  You will have three actuators, one for the floor vent, dash vent and defrost vent doors.  There's four hoses going to those three actuators.  Two of the four go to the defrost vent door actuator.