Been lurking here for some time, but no unique problems until now, got most of what I needed by searching the forums, but now I am stumped.

When I first got the truck, I had a problem with the temp control, which I understand is an electric motor-controlled blend door arrangement under the dash. The temp from the vents would be cold if the control was fully CCW (fully cold), but much warmer than that, the temperature went to what felt like full hot. Dealer worked it under warranty, and showed me a broken small plastic disc, which I guess now was from the shaft of the blend door motor.

A couple of years later, the same problem occurred, I was quoted $600+ to correct the problem again, when it recurred. I have lived with it ever since.

Lately, however, mostly after long runs (>30 mi) on the highway, as I'm decelerating on the ramp, the AC will go hot (not just uncooled air, heated air). The only way to recover cold air is to change the mode switch to OFF, wait a while, and then turn it on again. Sometimes this happens quickly, sometimes I have to wait a while before turning it back on to get cooled air again.

FWIW, before I did the research, I thought this might be a vacuum problem, so I checked the vacuum readings, and I get a consistent 27" of vacuum, on the road and at idle. No problem there.

My guess is that the control for the blend door that I have been living with for some time has deteriorated to the point that the door is not firmly held in the "cool only" position, and is moving when the truck slows down or is pointed downhill, or some such.

Does this make any sense to anyone. I really don't want to tear into anything without some confirmation that I'm heading in the right direction.

Any help GREATLY appreciated. Thanks!

 

You obviously have a blend door issue that is easily fixed, search on here for a "heater treater" I believe it's called, you may also need the electric drive motor for the blend door.
As for it getting hotter when you slow down I suspect the AC system needs a little freon and when you slow down the AC efficiency drops allowing the hot air to overcome the cold. You may also want to check your radiator if you haven't moved the puke bottle, if it's clogged it will reduce the airflow through the condenser also reducing the AC efficiency.

 

Thought that only applied to the 3rd gen trucks. Am I wrong?

 

Perhaps I have it wrong but there is available a small piece that goes on the end of the blend door shaft that stops it from breaking in the future. I found a link to the piece in question. http://heatertreater.net/Dodge%20Ram%2095-02.htm Heater treater also sells parts for the 3rd gen trucks.