Heater And Ac do there own thing

[jpellish]

Hey Guys I got a weird one for ya,
I will try to explain it as best as I can,
In my truck Ive noticed alot lately that when the heat or a/c is on, and at any fan speed, on any vent control, the controls do their own thing.
Example: if the setting is set to blow on your face it works fine when not hitting the throttle. When I hit the throttle the flow usually changes to the defrost vents. As soon as I let off the throttle it goes back to your face. It could be set on anything and it always changes. Pretty much it only changes whenever my foot gets heavy, Its never did it any other time so Im sure its caused by the throttle changing. I absouetly have no idea what it could be and my ears are open. Thanks -Joe

 

[jpellish]

add

i want to add when it changes it stays hot and when the a/c is on it stays cold. i know there are other similar threads on here, but i dont think our problems are the same. -Joe

 

[martin]

There should be a vacuum resevoir 'plastic tank' somewhere under the hood that helps to maintain a constant vacuum source. If it's cracked, missing or has a broken hose the ventilation system will default to windshield every time you are on the throttle.

 

[jpellish]

awesome thanks man I will look into it!!
-Joe