I'm talking about the cold/hot switch, blend door.

 

This is a great thread, thanks to everyone who has contributed. I have a 1998 Dodge Ram 1500 with the 5.2 and mine turns off the ac when I hit the gas and acts kinda wierd in general. The dealer isn't sure which part it is so I'm gonna call back with the part #. Really thanks guys!

 

Well it appears the ck valves did the trick.

 

Nice huh? This is a great thread. Now don't be a stranger, and do a search here for "plenum" before it's too late!

 

Did you get any on ya? : )

 

I'm workin on this issue now. I still have CC but I only get air/heat outta the defrost. Fro a wile it was all workin, but under strain (acceleration) it wiould just blow out of the defrost then go back to what ever setting I set it on. Now all I have is the defrost vent.

I wish there were pics of all the valves we need to check, I see there were some but not all of them (PCV and check). I'm a visual learner. Once I see it I can fix it. Also, a generic map of the whole vac system would be a huge help.

On a side note, ever since I've had the truck, I've had the check engine light on reading a code to the purge valve, well three new valves later, engine light is still on giving that code. This have anything to do with the vac system?

Thanks!

 

You need to check(trace) the hoses going from the solenoid to the canister for cracks/leaks, and remove it(the canister) and inspect for cracks in the plastic. Also disconnect the hoses from both ends and make sure they are not filled with charcoal.

 

Did you read through the whole thread? I think there were some pictures i there. They helped me alot!

 

What solenoid and what canister?

 

cannister purge solenoid, up on the passenger front fender, where a second battery would go.

cannister is under the passenger side rear of the cab.... or, a bit further back.