Barely Cooling the Air (everything checks out good)

Year: 1995
Make: Dodge
Model: Grand Caravan Conversion Van

Refrigerant: R134


Hi again guys...
The AC on my wifes Dodge Grand Caravan is barely producing cold air, everything is functioning properly with the exception of the air not being cooled.
It's a dual AC (R134) conversion van (High Top) made by PrimeTime. The air comes out at the same temp from both units. I recently (about 4-5 months ago) added freon to the system and to this day its still holding the charge (using that little pressure gauge with the color coded dial). So I'm not sure what could be wrong or what can I do to resolve this problem. Please help, we just moved to Southwest Florida and AC is a must down here... thank you!

UPDATE:
I had to refill the system...
But, after filling (guesstimating with the color coded gauge again) to about 40-43PSI @ 900RPM @ 85ºF. Reving the engine brings the pressure down to like 35PSI @ 2000RPM. The air comes out cold now, but is not enough to keep the inside at a confortable temperature. And NO the system does NOT work a better if you just set it for front A/C only. I have 2 color coded gauges (1 for each vehicle) and both give me the same reading...

Airflow is strong and good thru both units. But something I've experiense before is that the air chages direction if the RPM go too high, like if you're going to pass another vehicle or going up a steep hill that would kick the engine into overdrive, the high RPM (usually going over 3000RPM) causes the air direction to be directed at the windshield. Then as the RPM go back down the air direction is brought back down to the center direction. Not sure why it does this or if this has anything to do with air cooling performance.

I don't know if your conversion van has the Electronic Environmental control unit, Which is another name for the large Electonic Logic Board (ELB) that is located behind the HVAC selectors. The dial selectors and sliding temperature selector are integrated on this large ELB and the boys at Dodge discounted the risks of contamination failure modes. In any case, I had the same problem with my 97 Grand C, check my contributions to this forum for a more detailed analysis of the symptom/solution to your problem. In short though, you will most likely be replacing the ECU, a $400 part, because somewhere in the past, something spilled out of the cup holder (conveniently located by the HVAC engineers), and contaminated both the temperature and zone selector reostates that those sliders are connected to, and caused a malfunction (resistance either bridged or severed) of the control board.

It is simple to perform a diagnositic check of the board with some push button magic. Check my previous posting.
P_medica