jdmccright

It's been a while since I've been in here, so hope everyone is well. I've noticed that when I have the HVAC blower on and set to blow through the dashboard registers, then push the throttle down to accelerate (up a hill or away from a stop), the blower door will divert the airflow to the windshield. This says to me that I'm losing vacuum when I accelerate but don't know where to look. I just replaced all the vacuum lines abt 6 months ago due to tranny fluid contamination, so normal wear shouldn't be the reason. Any thoughts or experience in dealing with this? Thanks in advance for your help!

Added 9/18/06: This only happens when it is in blower mode. When the air conditioner is on, it blows normally no matter what I do to the throttle. Any ideas?

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Current Garage:
2003 Pontiac Vibe 1.8L AWD
2003 GMC Envoy XL (aka "fat-a$$") - K&N air filter, otherwise stock.
1995 Chevrolet C2500 2wd, 5.7L - K&N air filter, otherwise stock...my weekend hauler.
1992 Toyota Camry LE 2.2L - K&N air filter.

Vehicle History:
2004 4.7L Dakota Quad Cab 4x4
1996 GMC Jimmy 4wd
1992 Chevrolet S10 Ext. Cab 4.3L
1995 Honda ST1100...my first (and only) new vehicle.
1980 Yamaha XS400
1980 Mercury Bobcat...my first car.

grizz07

I had a similar problem with my 97 Jimmy. Into the dealer and they replaced the HVAC switch in the dash. It worked for awhile and quit again. Dealer eventually changed the defective switch and it is working again.