I am having the same problem with a 93 with the 3.3
I changed the fan, changed both relays, temp sensor, etc...
I ran a switch to the dash board to turn the fan on and off as needed.
I just orded a universal temp sensor from Jegs (16.99).
When it comes in I will mount it and use a realy to turn the fan on and off. The temp sensor is rated at 170f.
I will keep you posted.
Oh yea I also stoped by a Chrysler dealer and asked him about it and he was lost on why it did not work but for $85.00 per hour they would look at it. No thanks!