Caravan AWD V6-201 3.3L (1991)
Radiator Cooling Fan Motor: Description and Operation
Electric Fan Motor (Typical).
RADIATOR FAN CONTROL
Fan control is accomplished two ways. The fan always runs when the air conditioning compressor clutch is engaged. In addition to this control, the fan
is turned on by the temperature of the coolant which is sensed by the coolant temperature sensor which sends the message to the on-board computer.
The computer turns on the fan through the fan relay.
Switching through the on-board computer provides fan control for the following conditions.
1. The fan will not run during cranking until the engine starts no matter what the coolant temperature is.
2. Fan will always run when the air conditioning clutch is engaged.
3. On non-air conditioned vehicles or with air conditioning off the fan will run at vehicle speeds above about 40 mph only if coolant temperature
reaches 110°C (230°F) and will turn off when the temperature drops to 1O4°C (220°F). At speeds below 40 mph the fan switches on at 99°C (210
°F) and off at 93°C (2OO°F).
4. There also is included a method to help prevent "steaming" (water vapor evaporated by hot water circulating through the radiator evaporating
moisture on the outside of the radiator - and when there is no ram air to blow it under the vehicle) the fan will run only below 16°C (60°F)
ambient, from 38°C (100°F) to 97°C (195°F) coolant temperature. only at idle, and zero vehicle speed and then only for three minutes.
TEMPERATURE GAGE INDICATION
At idle with Air Conditioning off the temperature gage will rise slowly to about 5/8 gauge travel, the fan will come on and the gauge will quickly drop
to about 1/2 gauge travel - this is normal.
