How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Bob Your Own Question
Bob, Auto Tech
Category: Chevy
Satisfied Customers: 4087
Experience:  Plus 40 years GM, over 30 certified with Chevrolet, ASE certified Master Tech. (Expired, Retired)
Type Your Chevy Question Here...
Bob is online now
A new question is answered every 9 seconds

1999 Chevy Astro: van..s AC blows out the defrost and bottom..vents

Resolved Question:

My 1999 Chevy Astro van's AC blows out the defrost and bottom but will not switch to the main vents Please [email protected]
Submitted: 9 years ago.
Category: Chevy
Expert:  Bob replied 9 years ago.
Your heater system and AC doors are vacuum controlled. When vacuum to the system is lost, the system will only blow out of the defrosters as a fail safe. The normal thing on these is the hose on the back of the intake manifold, small black with a plastic hose and rubber connector, comes unhooked. It happens a lot when the engine cover is removed and then reinstalled. Check the vacuum connections of the motor and you will ,more than likely find and fix the problem. Thanks
Bob and 2 other Chevy Specialists are ready to help you