Thank you for the added info...........
"IF" yoiu replaced the Fan Relay Module, located on the left front frame, below the Air Cleaner Box,
then you need to have the PCM "Flashed", as the PCM is responsible for the operation of the Fan Relay Module. The Temperature Sensor triggers the PCM, which turns the Fan Relay Module "on".
There was a Chrysler Campaign for a limited number of Vans, that had a specific problem with the PCM & your V.I.N. identifies your Van as one of them.
Here is Chrysler Tech Bulletin below:
1998 Model Year Dodge Caravan and Grand Caravan; Plymouth Voyager and Grand Voyager; and Chrysler Town & Country (NS) Vehicles Equipped With a 2.4L, 3.3L or 3.8L Engine ("B", "G","R" or "L" in the 8th VIN Position) Built Through:
^ November 26, 1997 (MDH 112623) at the St. Louis South Assembly Plant ("B" in the 11th VIN Position)
^ December 1, 1997 (MDH 120109) at the Windsor Assembly Plant ("R" in the 11th VIN Position)
***The radiator fan relay on about 150,000 of the above listed vehicles, may not turn on the radiator cooling fans.
The software within the powertrain control module (PCM) may not operate or drive the solid state relay for the radiator fan correctly.
The vehicle could eventually exhibit an overheat condition due to cooling fan relay failure.This may cause the engine to overheat. To correct this condition, the radiator fan relay must be replaced and the Powertrain Control Module (PCM) must be reprogrammed (flashed).