I have a 99 Ram 1500.
While I run the AC (or Heat) out the front vents at normal cruze everything is good.
When I speed up the vent closes off and starts blowing out the defrost.
Anyone else see this?
Is there a quick easy fix or just live with it?

Sorry for posting twice..
I didn't see it post the first time...
F*&^ Newbie sorry.

 

Yes, there was a service bulitin about it I appoligize can't remember the number. Your HVAC switch is starting to go bad. Easy job for a DIY don't by a used switch I think the new factory one addressed the problem.

 

I fixed the one in my son's truck by replacing the vacuum check valve on the rt hand side of the throttle body. The vacuum line comes from the firewall on the pass. side and T's then goes into a small round check valve on the pass side of the intake, before finally entering the intake. I left the faulty valve in place as the local dodge dealer didn't have that exact one. I bought a larger one from them for 8 bucks and put in inline closer to the firewall. Took 15 mins and a/c works like new. This was on a 99 1500.