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So the A/C compressor doesn't engage, either? But the cooling fan does turn on when the car gets warm? Are you sure that you plugged in all of the electrical connectors to the A/C? All cars since the 1970s have a power connector to the A/C clutch and a low-pressure cutoff switch. Most cars since about the mid-80s also have a high-pressure cutoff switch on the compressor. Make sure all three are plugged in.

How did you determine that the system is full of freon? What is the static pressure reading (engine off)?

Does this car actually require discharging the A/C to change a timing belt? On many cars, you simply unbolt the compressor from its bracket and swing it to one side, without opening the system.
 

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OK. Most Mopars from early 1980s on are wired with the A/C compressor relay cascaded with the fan relay. That means that the fan relay must close in order for power to get to the A/C relay. So there probably is a computer signal that is sent to turn the fan on, but it's being lost somewhere. I'm not as familiar with the newer cars (mid-90s and on), but instead of a fan relay, the vans and some other vehicles have a solid state relay (MOSFET) which is the switch to turn the fan on. And there is a temperature probe, I believe, in the condenser, that triggers the fan. So maybe that probe is unplugged or damaged? Someone here who has owned a PT should know.
 
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