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Air is stuck on defrost. I see here that I need to check the…

Customer Question
Air is stuck on...

Air is stuck on defrost . I see here that I need to check the actuator door. I didnt know if it was electric or vacuum controlled.

Mechanic's Assistant: How long has this been an issue? How many miles are on the car?

Its a 1994 gmc vandura 2500 with 157xxx and not sure how long its been going on bought it like that

Mechanic's Assistant: Are you fixing your Vandura 1500 yourself? What have you tried so far?

It is a 2500 vandura if that makes a difference . yes I am a mechanic. So far i have tried to locate any broken vacuum lines and found some that came from the throttle body and went to a check valve then tee off one going to piece by distributor and then one went down to the front of the motor where it was just dangling so not sure where it goes thats why I was looking at your diagram

Submitted: 4 months ago.Category: GMC
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Answered in 5 minutes by:
3/20/2018
GMC Mechanic: K. Wiggins, ASE Certified Technician replied 4 months ago
K. Wiggins
K. Wiggins, ASE Certified Technician
Category: GMC
Satisfied Customers: 3,570
Experience: ASE Certified Technician, Associates Degree in Automotive Technology, 15+ years in the trade
Verified

Hello, it is vacuum operated. The T should go to a Vacuum tank, I'll post the HVAC vacuum schematic below. Let me know if I can help further

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