The first thing you must do, is realize this is likely not a problem with the A/C at all. A/C issues are EXPENSIVE to fix, so do not make it one until you KNOW it is the A/C. If the coolant control valve (the duovalve) is fully open, then anytime the engine is warm, you will get warm air even if the A/C is fine. The duovalve's default is wide open. If any wiring or connector corrodes or the fuse blows, you get full time hot air, period. So, is the A/C broke or is the heater coming on all the damn time? Which are we chasing? THere is an easy way to tell.

How I would go about this:

1. Start car, turn both climate control temperature ***** "fully blue", that is, to the coldest setting. This commands the duovalve to close.
2. Warm car to operating temperature (needed to almost 9am on the temp gauge).
3. Turn fan to high and check - with A/C off and ***** "full blue", you should have air from the vents essentially at ambient temperature, maybe a little warm but NOT HOT. Check all four vents.
4. If two on one side are OK, but the two on the other side are hot, your Duovavle is stuck open on one side. (Easy fix)
5. If all four are blowing hot, the duovalve is open on both sides; this is not a stuck valve but either a failure in the controller or a "no power to the duovalve" issue. (Potentially an easy fix)
6. If things work and you get no really HOT air, then the duovalve is ok, go to 7).
7. Now, hit the A/C button:
   1. If the red light on the A/C button does not come one, you have a controller problem. Bring the car to Dallas, Texas and I can fix it.
   2. If the red light comes on and the temperature of the air does not drop, but you hear the A/C clutch engage, you need someone good with auto A/C systems (and a lot of money).
   3. If the red light comes on and the temperature of the air does not drop, and you dont hear the A/C clutch engage, you need someone good with auto A/C systems who also can troubleshoot to determine if it is a sensor that has died or if the controller recognizes a condition that the ECU is designed to refuse to run the A/C. This will cost as much or more than 7-2 and is very hard to get fixed because we live in a culture of deep ignorance of electronics. (Which is why I make six figures. )
      
      
      

I realize you came looking for an easier answer than the above, and if it is the duovalve the fix will likely be easy and kinda cheap. But you MUST determine if this is an A/C issue or if it is a problem with the heat coming on when you do not want it to. MOST of the time, the issue is the duovalve is opening when it should not. Very common and not hard to fix.

If this really is an A/C issue, well, A/C issues can be expensive and hard to get fixed. If the system lost charge because the pump died or the condenser sprung a leak, its pretty easy to replace the bad items and make things work again;EXPENSIVE but not all that hard. I STRONGLY suggest you determine what the actual issue is before you take the car anywhere. Duovalves are an easy DIY fix at home or at many small shops.

If you take the car to a CHyrsler dealer, (see my sigline, don't be a dumbass), it will never get fixed. If you can find an MB dealer or German Auto Car Shopt that will work on it, they will probably have it fixed in a day but it will be EXPENSIVE, even if all it is, is the duovalve.