Engine Cooling Fan Buick Park Avenue I

MODEL IDENTIFICATION

BODY CODE DESIGNATIONS

DESCRIPTION

All FWD and some RWD vehicles use an electric cooling fan. The electric cooling fan is used for engine and A/C condenser cooling. Cooling fan operates when A/C is on and when engine coolant temperature exceeds a certain value.

OPERATION

High speed cooling fan is left fan (fan No. 2) and low speed cooling fan is right fan (fan No. 1). Powertrain Control Module (PCM) will energize low speed fan when engine coolant temperature exceeds 212°F (100°C) or when A/C is requested.

Left cooling fan will run at a higher speed when high speed fan is requested. Cooling fan will continue to run approximately 45 seconds after A/C request signal is gone.

When low speed cooling fan is energized, PCM will delay high speed cooling fan for approximately 6 seconds. When A/C refrigerant pressure exceeds 210 psi (15 kg/cm 2 ), PCM will energize high speed cooling fan. PCM will also energize high speed cooling fan when engine coolant temperature exceeds 226°F (108°C).

TROUBLE SHOOTING

Note. This article contains test charts which are part of General Motors Computerized Engine Controls. Only those charts required to test electric cooling fans are included. Other diagnostic information may be referenced while performing electric cooling fan diagnosis. For complete information on General Motors Computerized Engine Control systems, see appropriate article in the ENGINE PERFORMANCE section.

Trouble shoot cooling fan using appropriate C-12 charts provided. See COOLING FAN CHARTS . For cooling fan relay location, see COOLING FAN RELAY LOCATION table.

COOLING FAN RELAY LOCATION

SCAN TESTER

A variety of information is transmitted through Data Link Connector (DLC) terminal "E" or "M" depending on engine. This data is transmitted at a high frequency which requires a Tech 1 scan tester for interpretation. Several scan testers are available for diagnostic work. Scan testers other than Tech 1 scan tester will function and provide information for diagnostic work; however, some charts will specify a Tech 1 scan tester. Failure to use a Tech 1 scan tester, when specified, may result in incorrect diagnosis of a system.

CHART C-12A, COOLING FAN DIAGNOSIS 3.8L - VIN L & 1 (1 OF 4)

Right cooling fan (fan No. 1) is a low speed fan. Left cooling fan (fan No. 2) is a low and high speed fan. Power for fan motor goes through a 40-amp fusible link to terminal No. 1 of fan relays. Fan relays are energized when a ground circuit is completed through Powertrain Control Module (PCM) quad-driver. PCM energizes right cooling fan (fan No. 1) through PCM terminal GC4 when Engine Coolant Temperature (ECT) sensor indicates 212°F (100°C) or when A/C is requested. PCM energizes left cooling fan (fan No. 2) if A/C refrigerant pressure reaches 210 psi (14.8 kg/cm 2 ) or ECT sensor indicates 226°F (108°C).

Note. Test numbers refer to test numbers on diagnostic charts.

1. Using Tech 1 scan tester miscellaneous tests, FAN 1 control will cause PCM to ground circuit No. 1269. Right cooling fan (fan No. 1) should run.
2. Using Tech 1 scan tester miscellaneous tests, FAN 2 allows control of circuit No. 1270. Left cooling fan (fan No. 2) should run.
3. When jumpering A/C head pressure switch harness connector, PCM should energize left cooling fan (fan No. 2) on high speed.

Diagnostic Aids

An intermittent may be caused by a poor connection, rubbed-through wire insulation or a wire broken inside the wire insulation. Check PCM harness connector for backed out terminals. Connect a DVOM between affected terminal and ground. Wiggle related wires and connectors while watching DVOM for a voltage reading change. Ensure ECT sensor is not mis-scaled. See Diagnostic Trouble Code (DTC) 15 chart in appropriate article in the ENGINE PERFORMANCE section. Ensure engine cooling system functions properly.

Scheme 1

Scheme 2

CHART C-12B, COOLING ALWAYS ON 3.8L - VIN L & 1 (2 OF 4)

Note. Test numbers refer to test numbers on diagnostic charts.

Scheme 3

1. Checks if circuit No. 1269 is shorted to ground, which would keep relay closed at all times.
2. Checks if circuit No. 1270 is shorted to ground. If test light comes on, it indicates wire is shorted to ground. Continuing with chart diagnosis will isolate short.
3. If test light is off after disconnecting PCM, ensure circuit No. 1269 is not shorted to battery voltage. If circuit is not shorted to battery voltage, PCM is shorted internally.
4. If test light is off after disconnecting PCM, ensure circuit No. 1270 is not shorted to battery voltage. If circuit is not shorted to battery voltage, PCM is shorted internally.

CHART C-12C, NO LOW SPEED FAN 3.8L - VIN L & 1 (3 OF 4)

Note. Test numbers refer to test numbers on diagnostic charts.

Scheme 4

1. Checks for battery voltage at relay harness connector terminals No. 1 and 2.
2. Jumpering relay terminals No. 1 and 4 by-passes relay, which should cause fans to run if fan motors and wiring are okay.
3. Grounding Data Link Connector (DLC) test terminal should cause PCM to ground circuit No. 1269. At this point, test light should be on if PCM is good and circuit No. 1269 is not open.
4. Checks for battery voltage and ground to fan motor. Test light on at this point indicates a faulty fan motor connection or motor.

CHART C-12C, NO HIGH SPEED FAN 3.8L - VIN L & 1 (3 OF 4)

Note. Test numbers refer to test numbers on diagnostic charts.

Scheme 5

1. Test light should be on because left fan relay (fan No. 2) harness terminal No. 2 has battery voltage with ignition on.
2. Jumpering relay harness terminals No. 1 and 4 by-passes left fan relay (fan No. 2). If fan runs, fan relay is faulty.
3. Checks circuit No. 1270 back to PCM. If circuit No. 1270 is okay, left fan relay (fan No. 2) is bad.

Cooling Fan Wiring Diagram (Eighty-Eight & Ninety-Eight) (3.8L VIN L & 1). Scheme 6

Cooling Fan Wiring Diagram (LeSabre & Park Avenue) (3.8L VIN L & 1). Scheme 7

Cooling Fan Wiring Diagram (Bonneville) (3.8L VIN 1). Scheme 8

See also:
• COOLING FAN CHARTS