that is just the way it is ,it's a clutch fan and it will stay turning until the fan stops.
It is not a clutch fan it has two fans and they are electric, but i have the same problem they run and dont turn off utill the battery dies.
If the AC is on, this is normal.
location of engine cooling fan sensor
If you are referring to the electric engine radiator fan, there should a safety recall for a free replacement or repair. I had one done on my 1995 Mercury Sable. But I don't know if the recall goes back that far to 1988. Go to the Federal Government's National Highway Safety web page to see.
Could be a bad temperature sensorUsually located at the rear of the radiator about 1/3 down from the top
Under dash at RH side, mounted with 3 bolts. R&I about 3 minutes.
It's been a few years since I sold mine, but it should be under the glove behind the kick panel...
Serpentine / accessory drive belts price around $15-30.Don't go cheap on this particular item.See "Related Questions" below for tons more about Sable serpentine belts.
Sable's fan mail address is Wayne Sable, The Culbertson Group, 9107 Wilshire Blvd., Suite 450, Beverly Hills, CA 90210. He will receive all of his fan mail addressed to this address.
The radiator fluid is low or you parked the car at am angle.
The temperature should rise to "normal" or 210F (dependent on which gauge that car has in it). If it is going above that (overheating) then the electric fan is not working; fan motor failure, relay failure, fuse, temperature sensor failure, wiring fault).
Not to assume anything...There are two primary fans on the typical vehicle: engine / radiator cooling fans and the heater blower fan.Both are covered in the "Related Questions" below.
picture of the fan relay for 1993 mercury topaz