Electra V6-231 3.8L VIN C SFI (1988)
Wiring Diagram for Chart C-12A Coolant Fan Check
CHART C-12C
NO LOW SPEED FAN COOLANT FAN CHECK
Circuit Description:
Power for the fan motor comes through the fusible link to terminal "1" on all relays. The relays are energized when current flows to ground through the
ECM (quad-drivers).
Low speed Relay - The ECM energizes the relay through terminal "YC2" when the coolant temperature reaches 101 C (208 degrees F).
High Speed Relay - The high speed relay is energized by the ECM or the A/C pressure switch. If the A/C refrigerant pressure reaches 275 psi (1896 kPa)
or the coolant temperature reaches 108 C (226 degrees F), the high speed fan relay is energized.
Test Description:
Numbers below refer to circled numbers on the diagnostic chart.
1.
Checks for battery voltage at relay harness connector.
2.
Jumpering terminals "B" to "D" bypasses the relay, which should cause the fan to run if fan motor and wiring to the motor are good.
3.
Grounding the test terminal should cause the ECM to ground CKT 535. At this point, the test light should light, if the ECM is good and CKT
535 isn't open.
4.
This checks for battery+ and ground to the fan motor. A test light "ON" at this point indicates a faulty fan motor connection, motor connection,
or motor.
