GHinton:
Go to Harbor Freight or any store for that matter and buy yourself a digital temp probe (a bar-b-que meat thermometer will work).
Install the thermometer probe in center dash outlet and record the temperature on a hot day. Typically, if you see a 30F temp difference between ambient and outlet, you are doing very good, especially if its extremely humid.
It is much harder on the AC system to remove moisture from the air than it to cool dry air. With hot humid air, the AC capacity is being taxed to remove the moisture. That is why it is good to run in recirc on humid days, at least until you are comfortable.
Also, if you run on HI blower, the outlet air temps will be higher than if you run on speed 1 or 2.
From the Dodge SM, it must be at least 70F for the dealer to accurately test the system. Test is simple, set temp to full cold, set blower to HI, push recirc switch and AC switch, run engine at 1000 rpm for 5 min.
At 80F ambient, DS center outlet temp should be 45F or less. At 90 or 100F, it should be 55F. Please remember that this is in recirc, so if you are in outside air mode, the outlet temp will be closer to the 30F temp differential compared to ambient. (Ex: 100F outside, 70F at outlets)
Most common cause of warm air: refrigerant leaks. Check the accumulator inlet and outlet connections, they are those cheap-ass spring lock couplings that are fantastic for manufacturing but really stink at sealing the system. Look for oily residue at all connections for a possible leak.
Hope this helps.