View Single Post
  #2  
Old 10-03-2007, 06:40 PM
BNaylor's Avatar
BNaylor BNaylor is offline
AF Moderator
 
Join Date: Jan 2005
Posts: 18,017
Thanks: 30
Thanked 54 Times in 42 Posts
Re: AC/Heater won't switch vents

Check for a loose or missing accessory vacuum which originates at the intake manifold. It loops by the firewall and around to the passenger side inner fender. You'll see a junction/coupler plastic connection next to the battery and engine compartment fuse box. Check it first. Look for any cracking along the complete plastic vacuum line. From there it inputs the main wiring harness and into the cabin to the HVAC system.

The HVAC vacuum actuators use engine vacuum for control via the climate control head unit.



__________________

'08 Pontiac Grand Prix GXP (Dark Slate Metallic) - LS4 5.3L V8
'02 Oldsmobile Alero GL2 - LA1 3400 V6
'99 Buick Regal LS - L36 Series II 3800 V6
'03 Honda CR250R MX - 2 Stroke 250cc
'97 Pontiac Grand Prix GTP - L67 Series II 3800 V6 Supercharged (Sold)
Timeslip 08/12/06

AF Community Guidelines
Reply With Quote