I have an 06 Dodge Ram 2500 with vent door problems. The defrost vent stays open on every function and the floor vent no longer works. Any help on how to diagnose this or fix it would be great. Thanks

 

Unfortunately a very common problem on 3rd gen trucks. Best solution is the upgraded blend door from HeaterTreater.net

IIRC, they also have replacement instructions with pics on their website.

Dodge Ram '02-'08 - '02 - '08 - Ram - Dodge

 

I pulled the blower motor and found that the re-circ vent door drive coupler broke and let the door fall down and block air flow. Removed door and all air flow was good except cannot change between re-circ and fresh air which for me is no big deal. At least I have good air flow for both heat and A/C. I found this fix doing a search for re-circ door or maybe it was blend door.

 

This is a good thread on the HVAC case.

https://www.dieseltruckresource.com/...rstood-210483/

Taking it out isn't all that difficult, but it requires evacuating the AC, draining the coolant and removing the dash.

I believe there were updated part numbers for the upper and lower housings that have improved tabs that interact with the couplers between the motors and door stems to limit travel.

There is also the heater treater option as noted above, which I haven't done but apparently involves cutting into the hvac cases in place, to install their metal doors.

If you do decide to pull it, replacing the heater core and AC evaporator might be worth considering. It took me like 4 hours to get everything out and apart, and probably close to that to put everything back together, but I was working carefully.

 

Thanks for the info but it looks like the blind door for it is broke.