Skylark V6-204 3.3L VIN N FI (1989)
Chart C-12A Wiring Diagram
CIRCUIT DESCRIPTION:
Battery voltage to operate the cooling fan motor is supplied to relay terminal "1". Ignition voltage to energize the relay is supplied to relay terminal "2".
When the ECM grounds CKT 535, the relay is energized and the cooling fan is turned "ON". When the engine is running, the ECM will turn the cooling
fan "ON" if the conditions for a coolant temperature sensor trouble code (14 or 15) are present or:
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The A/C is "ON" and vehicle speed is less 30 mph (48km/h).
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The coolant temperature is greater than 100~C (212~F).
TEST DESCRIPTION:Numbers below refer to circled numbers on the diagnostic chart.
1.
Test light should be "ON" as the ignition switch is turned "ON."
2.
Test light should be "ON" as grounding the ALDL turns the QDM "ON" providing current flow to ground.
3.
Test light should be "ON" as terminal is direct from B+.
DIAGNOSTIC AIDS:
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If the owner complained of an overheating problem, it must be determined if the complaint was due to an actual boilover, or the hot light, or
temperature gauge indicated over heating.
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If the gauge, or light, indicates overheating, but no boilover is detected, the gauge circuit should be checked. The gauge accuracy can, also, be
checked by comparing the coolant sensor reading using "Scan" tool and comparing its reading with the gauge reading.
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If the engine is actually overheating, and the gauge indicates overheating, but the cooling fan is not coming "ON", the coolant sensor has
probably shifted out of calibration and should be replaced.
