97+ hvac issue

J

JJacobs

NAXJA Forum User

Location

Fort Collins CO

• Oct 7, 2009

• #1

I'd like to get an idea what's up here before I tear the dash out and decommission the vehicle for a day or more. Something is broken in the defrost door area. The door doesn't do what it should and when the blower is turned up the door gets blown shut with a nice bang. All other modes are present and accounted for. Do these things break the door, the actuating arm, the servo...?

Thanks.

 

W

winterbeater

NAXJA Forum User

Location

Royal Oak, Michigan

• Oct 7, 2009

• #2

The heat blend door is more known for breaking. The defrost problem is usuall bad vacuum, but that doesn't sound like you. I'd pull the vacuum motor off and try working it by hand to see what it feels like. I guess it could be the linkage between the motor and the door.

 

J

JJacobs

NAXJA Forum User

Location

Fort Collins CO

• Oct 8, 2009

• #3

Must not be a real common problem then. I need to get it fixed before nasty cold hits (tomorrow?)

That's right, it will push hot air out defrost on low until the higher airflow hits on 2,3,4 and bang the door shuts. Amusingly, when the fan is on high, mode defrost and I switch to dash it makes a neat dive-bomberish descending whistle noise.

 

joe_peters

NAXJA Forum User

Location

Grants Pass, OryGun

• Oct 8, 2009

• #4

Sounds like a vacuum leak/bad vacuum motor.

 

J

JJacobs

NAXJA Forum User

Location

Fort Collins CO

• Oct 12, 2009

• #5

Removed dash, found broken defrost door actuating arm. It's a separate piece that pushes into the end of the door and engages the actuator. No longer available separately, must buy whole plenum upper half. So I used some plastic weld epoxy and a screw down the middle for good measure. Thinking something must have made its way down the duct and jammed the door.

 

kastein

NAXJA Member

NAXJA Member

Location

Rainy side of Washington

• Oct 12, 2009

• #6

I'd junkyard a replacement personally. I hate paying a lot for parts, especially ones that don't really see that much wear from mileage, just age.

 

J

JJacobs

NAXJA Forum User

Location

Fort Collins CO

• Oct 12, 2009

• #7

I would have- but then you have to go tearing apart dashboards in junkyards. While that's fun and all, it's a little more of an endeavor than just gluing and screwing the thing back together and going on your way.