2nd Gen Non-Engine/Transmission Vent or AC Blows Hot air after initially working properly

[MEwoldt]

2000 dodge ram 2500 diesel 4x4. Assumptions: truck is at normal operating temperature.



Scenario:

If i select normal vent, regular AC or Max AC, the truck initially will work as advertised. Then it sounds like a "flapper door" or something closes and hot air begins to blow out all vents.



I haven't tried different settings like floor or defrost but since this affects both AC and the vent it led me to believe it's not an AC problem.



Any ideas?

 

[Ram4Sam]

Check the vacuum line from the vac pump to where the vac line enter the firewall. My truck recently started doing wacky stuff similar to your problem, I found a broken/rotten conection under the back hood gasket. Solved my issue.



Sam

 

[MEwoldt]

Thanks Sam,

Turns out it was the little black interposer that connects the blend door actuator motor with blend door "axle". The little sucker was cracked and split open like an egg. Here is the web site that explained the issue and another that has a replacement part for $30... in case you run across this issue.

Dodge Ram 1995, 1996, 1997, 1998, 1999, 2000, 2001, blend door auto AC heat replacement part
Blend door fix - DodgeForum.com

 

[Ram4Sam]

I had seen that link somewhere before and thought that might be the problem, I started with the easy stuff first and found the split hose.



Sam