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ICEMAN537
Apr 27, 2009, 06:40 PM
I have a F150 truck ,lately when I have the AC on and press on the gas petal--
The air goes from the front vents to the defrost vents, let off the gas and it goes back to
The front vents?

Is it a vacumn problem or the air select switch problem?

Iceman537

TxGreaseMonkey
Apr 27, 2009, 06:44 PM
Vacuum pressure drops, as the throttle plate opens. Pressure drops are affecting the blend doors.