Grand Voyager V6-3.8L VIN L (1999)
Radiator Cooling Fan Motor Relay: Description and Operation
SOLID STATE FAN RELAY-PCM OUTPUT
The radiator fan runs at a variable speed depending on coolant temperature and A/C system pressure. The radiator fan circuit contains a Solid State
Fan Relay (SSFR).
A 5 volt signal is supplied to the SSFR. The PCM provides a pulsed ground for the SSFR. Depending upon the amount of pulse on time, the SSFR
puts out a proportional voltage to the fan motor at the lower speed. For instance, if the on time is 30 percent, then the voltage to the fan motor will
be 3.6 volts.
When engine coolant reaches approximately 102 °C (215 °F) the PCM grounds the SSFR relay. If engine coolant reaches 207 °C (225 °F) the
PCM grounds the high speed ground relay and high speed fan relay. If the fan operates at high speed, the PCM de-energizes the high speed relay
and high speed ground relay when coolant temperature drops to approximately 101 °C (214 °F). When coolant temperature drops to 101 °C (214 °
F) the fan operates at low speed. The PCM de-energizes the low speed relay when coolant temperature drops to approximately 93 °C (199 °F).
Also, when the air conditioning pressure switch closes, the fan operates at high speed. The air conditioning switch closes at 285 psi ± 10 psi.
When air conditioning pressure drops approximately 40 psi, the pressure switch opens and the fan operates at low speed.
Fan Control Module
The SSFR relay is located on the left front inner frame just behind the radiator.
