Chrysler Repair: radiator fans dont come on, radiator fans, fuse box

Question
Hi,

My town and country was rear ended recently and it in turn rear ended the car in front, resulting in cracked front bumper and a cracked radiator, losing all the antifreeze. I brought it home and repaired the radiator and reinstalled with new antifreeze, no leaks. Car starts fine but the fan is not kicking in. I tested the fan and all three relays and fuses and they all checked out. I understand there is a fourth relay hidden somewhere that I can't locate. Where is it and what other TS possibilities are involved?

I received this response from a tech here whose account has been deactivated:

The last controller is the PCM. The computer behind the left headlight. Check the lower connector on pin 75 (light green with a dark blue stripe)for continuity between the plug and fan relay. The relay in the underhood fuse box is temp controlled, while the other 2 are low and high speed for the a/c system. To find out if the fan itself may be the problem, run the engine and have the heating system on full heat, full defrost. The a/c compressor should cut in and the fan starts. If it doesn't. it might be the fan motor or the connection.
   
The fan checks out. I pulled out the PCM and inspected it. There is no pin 75 anywhere. There seems to be another controller right underneath the battery. I checked that out too and thats where I found the color description he was talking about, but there was no pin 75 there either. On both, the pins are up to 60. Right now, I just jumped the refrigerant temp sensor and the fan is always on. I need a better diagnostics please, and a exploded diagram of parts location and where exactly to test continuity or whatever else needs checking. Thanks.

Answer
Hi Benjamin,
Can you tell me the year of this van, and also which engine do you have?
If jumping the temp sensor plug, or simply pulling the plug causes the fans to run, then the fan circut itself would on first inspection appear to be OK. Check the temp sensor to see if it reads in the range of 1000 ohm when the engine is warmed up, which is what it should be. When it is cold it should read 10-14k ohms and then drop as the engine warms up. Check that out and then tell me the answer as to year and engine. Up to '95 the controllers for the engine had one 60-pin plug, but after that they have two 40-pin plugs. But I need to know exactly what is the year and engine as that is also a changing circuit over the years.
Roland