LSS V6-3.8L VIN K (1997)
Radiator Cooling Fan Motor: Description and Operation
Circuit Operation
The Powertrain Control Module (PCM) controls both Cooling fan motors by controlling two relays through two outputs. There are two modes of cooling
fan operation: low speed and high speed. Whenever the PCM provides a fans ON request signal, both fans run.
Low Speed Operation
Low speed cooling fan operation occurs when the PCM grounds the low speed cooling fan coil on CKT 335 (DK GRN). The relay energizes and
applies voltage to both the LH and RH cooling fan motors. Power is supplied to the motors through CKT 742 (RED), the low speed cooling fan
relay contacts.CKT 409 (LT BLU) and CKT (1150) (BLK) to ground G104.
High Speed Operation
The cooling fans run at high speed when the PCM grounds the high speed cooling fan relay on CAT 473 (DK BLU). The relay energizes and
applies voltage to both the LH and RH cooling fan motors. Power is supplied to the LH motor through CKT 532 (BLK). the high speed cooling
fan relay contacts, and CKT 1150 (BLK) to ground C 104. Power is also supplied to the RH cooling fan motor through CKT 532 (BLK), the
internal resistors of the LH cooling fan motor, CKT 409 (LT BLUE) and CAT 1150 (BLAKE) to ground G104.
