A/C changes vents as you speed up???

[Stone Dragon]

I have a '99 XL, and when you press on the gas, the a/c air will change from the dash vents, then to the defrost, then to the floor. If you let off it will come back to the dash vents. Any Ideas? It acts like a vacuum issue. I have a Ford escape doing the same thing, just not as bad. Thanks!

[SanDiegoXJ]

Well, I know on my '94 the vents are actuated by a vacuum line to the intake manifold....you could have a crack in the line.

[lilredwagn]

You didn't recently change your bumper or decide to remove the vacuum canister, did you?

[Stone Dragon]

You didn't recently change your bumper or decide to remove the vacuum canister, did you?
I did! I moved it for a new bumper.

[Slip Kid]

I did! I moved it for a new bumper.

you've got a leak! check the hoses and you may want to clean them out as well