Have 1999 2500 4wd with 5.9 gas engine. Started having vacumn leaks. I assume thats what the problem is, cause when you put a load on the engine, the ac vents close. Also gas milage getting worse. Anyone having suggestons give me a holler. Thanks.

its ur check valve on your brake booster, change it, takes 2mins!

all its doin is losin the vacuum to hold the doors open, it makes the air come through the defrost vents.

try checking out dodgeforum.com... lots of good ram info there!