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Electric Cooling Fans Buick Century VI

Cooling Fan 9 illustrations ~4981 words

IDENTIFICATION

Body Code (1)Model
"W"Century
"W"Regal
(1) Vehicle body code is 4th character of VIN.
(1)Vehicle body code is 4th character of VIN.

MODEL IDENTIFICATION

DESCRIPTION & OPERATION

CAUTIONWhen battery is disconnected, vehicle computer and memory systems may lose memory data. Driveability problems may exist until computer systems have completed a relearn cycle. See COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION before disconnecting battery.

3.1L (LG8) & 3.8L (L36 & L67)

The engine cooling fan system consists of two electrical cooling fans and three fan relays. The relays are arranged in a series/parallel configuration that allows the Powertrain Control Module (PCM) to operate both fans together at low or high speeds. The cooling fans and fan relays receive battery positive voltage from the underhood accessory wiring junction block. The ground path is provided at G117.

During low speed operation, the PCM supplies the ground path for the low speed fan relay through the low speed cooling fan relay control circuit. This energizes the cooling fan 1 relay coil, closes the relay contacts, and supplies battery positive voltage from the cool fan 1 fuse through the cooling fan motor supply voltage circuit to the left cooling fan. The ground path for the left cooling fan is through the cooling fan 2 relay and the right cooling fan. The result is a series circuit with both fans running at low speed.

During high speed operation the PCM supplies the ground path for the cooling fan 1 relay through the low speed cooling fan relay control circuit. After a 3-second delay, the PCM supplies a ground path for the cooling fan 2 relay and the cooling fan 3 relay through the high speed cooling fan relay control circuit. This energizes the cooling fan 2 relay coil, closes the relay contacts, and provides a ground path for the left cooling fan. At the same time the cooling fan 3 relay coil is energized closing the relay contacts and provides battery positive voltage from the cool fan 2 fuse on the cooling fan motor supply voltage circuit to the right cooling fan. During high speed fan operation, both engine cooling fans have there own ground path. The result is a parallel circuit with both fans running at high speed.

A diode is in parallel with each of the cooling fan motors. This diode absorbs a voltage surge and protects the vehicles electrical system. This surge results from the initial start-up of the cooling fan motor.

The PCM commands Low Speed Fans on under the following conditions

  1. Engine coolant temperature exceeds approximately 223°F (106°C).
  2. When A/C is requested and the ambient temperature is greater than 122°F (50°C).
  3. A/C refrigerant pressure exceeds 190 psi (1310 kPa).
  4. After the vehicle is shut off if the engine coolant temperature at key-off is greater than 284°F (140°C) and system voltage is more than 12 volts. The fans will stay on for approximately 3 minutes.

The PCM commands High Speed Fans on under the following conditions

  1. Engine coolant temperature reaches 230°F (110°C).
  2. A/C refrigerant pressure exceeds 240 psi (1655 kPa).
  3. When certain DTCs set.

COMPONENT LOCATION

ApplicationLocation
"W" BodyInside Electrical Center At Right Side Of Engine Compartment

COOLING FAN RELAY LOCATION

PROGRAMMING

CAUTIONWhen battery is disconnected, vehicle computer and memory systems may lose memory data. Driveability problems may exist until computer systems have completed a relearn cycle. See COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION before disconnecting battery.

POWERTRAIN CONTROL MODULE (PCM)

To program Powertrain Control Module (PCM) for 3.1L engines, see POWERTRAIN CONTROL MODULE under PROGRAMMING in SELF DIAGNOSTICS article in FAULT ISOLATION under ENGINE PERFORMANCE. To program PCM for 3.8L engines, see POWERTRAIN CONTROL MODULE under PROGRAMMING in SELF DIAGNOSTICS article in FAULT ISOLATION under ENGINE PERFORMANCE.

TROUBLE SHOOTING

CAUTIONWhen battery is disconnected, vehicle computer and memory systems may lose memory data. Driveability problems may exist until computer systems have completed a relearn cycle. See COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION before disconnecting battery.

PRELIMINARY INSPECTION

Verify customer complaint by operating suspecting system. Visually inspect for obvious signs of mechanical and electrical damage. Inspect for blown fuses and damaged relays. Replace as necessary. See RELAY ELECTRICAL CENTER under REMOVAL & INSTALLATION.

Inspect for loose or corroded connections, damaged wiring harnesses and/or switches. Check for a broken or partially broken or partially broken wire inside insulation, which could cause system malfunction but prove good in a continuity/voltage check with system disconnected. Ensure any aftermarket electronic equipment is properly installed. If fault is found, repair as necessary. If no fault is found, perform self-diagnostics. See SELF-DIAGNOSTIC SYSTEM .

SELF-DIAGNOSTIC SYSTEM

WARNINGVehicles may be equipped with a PCM using an Electronically Erasable Programmable Read Only Memory (EEPROM). When replacing PCM, new PCM must be programmed. See PROGRAMMING .
CAUTIONWhen battery is disconnected, vehicle computer and memory systems may lose memory data. Driveability problems may exist until computer systems have completed a relearn cycle. See COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION before disconnecting battery.

To help save diagnostic time, check cooling system fluid level, water pump belt condition and tension. Always check for blown fuses or fusible links before proceeding with any testing. If fuses are blown, locate and repair short circuit before replacing fuses. Ensure all related relay and wire harness connections are clean and tight. Repair as necessary. See WIRING DIAGRAMS .

Using Scan Tool

DTCs are retrieved using a Tech 2® scan tool or other OBD-II compatible scan tool connected to OBD-II 16-pin Data Link Connector (DLC). See DIAGNOSTIC TESTS . DLC is located below left side of dash. If no DTC's exist, repair by symptom. See SYMPTOM INDEX table under SYSTEM TESTS.

CLEARING DIAGNOSTIC TROUBLE CODES

There are 3 methods to clear DTCs.

Scan tool is preferable way to clear DTC information. Freeze frame and failure record data will also be cleared. PCM adaptive learning and system monitors will only be cleared for those system which had a stored DTC. A current DTC Last Test Failed clears when the diagnostic runs and passes.

Disconnecting Battery

Note. On many OBD-II systems, PCM will retain memory for an extended period of time with battery disconnected. Memory may be retained for several days.

Disconnecting PCM power or battery ground will clear all PCM memory including DTCs, freeze frame, failure records, adaptive learning and system monitors.

Warm-Up Cycles

The PCM uses warm-up cycles to run some diagnostics and to clear any Diagnostic Trouble Codes (DTCs). A warm-up cycle occurs when the engine coolant temperature increases 72°F (22°C) from the start-up temperature. The engine coolant must also achieve a minimum temperature of 160°F (71°C). The PCM counts the number of warm-up cycles in order to clear the Malfunction Indicator Light (MIL). The PCM will clear the DTCs when 40 consecutive warm-up cycles occur without a malfunction.

DIAGNOSTIC SYSTEM CHECK (ENGINE COOLING)

  1. Install a scan tool. Does the scan tool power up? If so, go to step 2 . If not, go to appropriate BODY CONTROL MODULES article under COMMUNICATION DEVICES in ACCESSORIES & BODY, CAB.
  2. Turn on the ignition, with the engine off. Attempt to establish communication with the instrument cluster and powertrain control modules. Does the scan tool communicate with the control modules? If so, go to step 3 . If not, go to appropriate BODY CONTROL MODULES article under COMMUNICATION DEVICES in ACCESSORIES & BODY, CAB.
  3. Select the powertrain control module display DTC's function on the scan tool. Does the scan tool display any DTC's? If so, go to step 4 . If not, go to «SYSTEM TESTS»(/buick/century/vi-1997-2005/remont/cooling-fan/#electric-cooling-fans__system-tests) .
  4. Does the scan tool display any DTCs which begin with a "U"? If so, go to appropriate BODY CONTROL MODULES article under COMMUNICATION DEVICES in ACCESSORIES & BODY, CAB. If not, see «DTC P0480 OR DTC P0480: LOW OR HIGH SPEED COOLING FAN RELAY CONTROL CIRCUIT»(/buick/century/vi-1997-2005/remont/cooling-fan/#electric-cooling-fans) .

Circuit Description

Battery positive voltage is supplied to the cooling fan 1 relay from the cool fan 1 fuse. The powertrain control module (PCM) controls the cooling fan 1 relay by grounding the low speed cooling fan relay control circuit via an internal solid state device called a driver. The primary function of the driver is to supply the ground for the component being controlled. Each driver has a fault line which is monitored by the PCM. When the PCM is commanding a component on, the voltage potential of the control circuit should be low (near zero volts). When the PCM is commanding the control circuit to a component off, the voltage potential of the circuit should be high (near battery voltage). If the fault detection circuit senses a voltage other than what is expected, the DTC will set.

The PCM will monitor the control circuit for a short to ground, a short to voltage, an open circuit, an open relay coil, an internally shorted or excessively low resistance relay coil. When the PCM detects any of the above conditions, the DTC will set and the affected driver will be disabled.

Conditions for Running the DTC

The ignition is ON. The system voltage is 9.0-18.0 Volts.

Conditions for Setting the DTC

An improper voltage level has been detected on the low speed cooling fan relay control circuit. The above conditions are present for at least 30 seconds.

Action Taken When the DTC Sets

The PCM will illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test has been run and failed. The PCM will store conditions which were present when the DTC set as Freeze Frame and Failure Records data.

Conditions for Clearing the MIL/DTC

The PCM will turn OFF the MIL during the third consecutive trip in which the diagnostic has been run and passed. The History DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction. The DTC can be cleared by using the scan tool.

Diagnostic Aids

If the condition is not present, test for intermittent and poor connections in wiring systems. Review the freeze/failure records vehicle mileage since the diagnostic test last failed. This may help determine how often the condition that caused the DTC to be set occurs.

Testing

  1. Did you perform the Engine Cooling Diagnostic System Check? If so, go to step 2 . If not, go to «DIAGNOSTIC SYSTEM CHECK (ENGINE COOLING)»(/buick/century/vi-1997-2005/remont/cooling-fan/#electric-cooling-fans__diagnostic-system-check-engine-cooling) under SELF-DIAGNOSTICS SYSTEM.
  2. Install a scan tool. Turn on the ignition, with the engine off. With a scan tool, command the fans low speed on and off. Does the cooling fan 1 relay turn on and off with each command? If so, go to «DIAGNOSTIC AIDS»(/buick/century/vi-1997-2005/remont/cooling-fan/#electric-cooling-fans__diagnostic-aids) . If not, go to step 4 .
  3. With a scan tool, command the fans high speed on and off. Do the cooling fan 2 and the cooling fan 3 relays turn on and off with each command? If so, go to «DIAGNOSTIC AIDS»(/buick/century/vi-1997-2005/remont/cooling-fan/#electric-cooling-fans__diagnostic-aids) . If not, go to step 6 .
  4. Turn off the ignition. Disconnect the cooling fan 1 relay. Turn on the ignition, with the engine off. Probe the battery positive voltage circuit of the cooling fan 1 relay with a test lamp that is connected to a good ground. Does the test lamp illuminate? If so, go to step 5 . If not, go to step 12 .
  5. Connect a test lamp between the low-speed cooling fan relay control circuit and the battery positive voltage circuit of the cooling fan 1 relay. With a scan tool, command the fans low speed on and off. Does the test lamp turn on and off with each command? If so, go to step 13 . If not, go to step 9 .
  6. Turn off the ignition. Disconnect the cooling fan 2 relay. Probe the battery positive voltage circuit of the cooling fan 2 relay with a test lamp that is connected to a good ground. Does the test lamp illuminate? If so, go to step 7 . If not, go to step 12 .
  7. Turn on the ignition. Connect a test lamp between the control circuit of the cooling fan 2 relay and the battery positive voltage circuit of the cooling fan 2 relay. With a scan tool, command the fans high speed on and off. Does the test lamp turn on and off with each command? If so, go to step 15 . If not, go to step 8 .
  8. Turn off the ignition. Disconnect the cooling fan 3 relay. Turn on the ignition with the engine off. Connect a test lamp between the control circuit of the cooling fan 3 relay and the battery positive voltage circuit of the cooling fan 3 relay. With a scan tool, command the fans high speed on and off. Does the test lamp turn on and off with each command? If so, go to step 14 . If not, go to step 9 .
  9. Does the test lamp remain illuminated with each command? If so, go to step 11 . If not, go to step 10 .
  10. Test the control circuit of the appropriate relay for a short to voltage or an open. Did you find and correct the condition? If so, go to step 22 . If not, go to step 16 .
  11. Test the control circuit of the appropriate relay for a short to ground. Did you find and correct the condition? If so, go to step 22 . If not, go to step 16 .
  12. Test the battery positive voltage circuit for a short to ground or an open. Did you find and correct the condition? If so, go to step 22 . If not, go to step 17 .
  13. Inspect for poor connections at the cooling fan 1 relay. Did you find and correct the condition? If so, go to step 22 . If not, go to step 18 .
  14. Inspect for poor connections at the cooling fan 3 relay. Did you find and correct the condition? If so, go to step 22 . If not, go to step 19 .
  15. Inspect for poor connections at the cooling fan 2 relay. Did you find and correct the condition? If so, go to step 22 . If not, go to step 20 .
  16. Inspect for poor connections at the harness connector of the PCM. Did you find and correct the condition? If so, go to step 22 . If not, go to step 21 .
  17. Repair the cooling fan motor supply voltage circuit for a short to ground. Did you complete the repair? If so, go to step 22 .
  18. Replace the cooling fan 1 relay. After repairs are complete, go to step 22 .
  19. Replace the cooling fan 3 relay. After repairs are complete, go to step 22 .
  20. Replace the cooling fan 2 relay. After repairs are complete, go to step 22 .
  21. Replace the PCM. See «POWERTRAIN CONTROL MODULE»(ref-157368-S04866010042003081100000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION article in ENGINE PERFORMANCE. After repairs are complete, go to step 22 .
  22. Use the scan tool in order to clear the DTC's. Operate the vehicle within the conditions for running the DTC as specified in the supporting text. Does the DTC reset? If so, go to step 2 . If not, system OK.

SYSTEM TESTS

CAUTIONWhen battery is disconnected, vehicle computer and memory systems may lose memory data. Driveability problems may exist until computer systems have completed a relearn cycle. See COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION before disconnecting battery.
SymptomTest
Cooling Fan Always OnA
Cooling Fan InoperativeB

SYMPTOM INDEX

TEST A: COOLING FAN ALWAYS ON

  1. Did you perform the engine cooling diagnostic system check? If so, go to step 2 . If not, go to «DIAGNOSTIC SYSTEM CHECK (ENGINE COOLING)»(/buick/century/vi-1997-2005/remont/cooling-fan/#electric-cooling-fans__diagnostic-system-check-engine-cooling) under SELF-DIAGNOSTIC SYSTEM.
  2. Turn on the ignition, with the engine off. Are one or both cooling fans on? If so, go to step 3 . If not, test for intermittent and poor connections in wiring systems.
  3. Are both cooling fans running continuously? If so, go to step 5 . If not, go to step 4 .
  4. Remove the cooling fan 2 relay. Did the right cooling fan turn off? If so, go to step 8 . If not, go to step 6 .
  5. Remove the cooling fan 1 relay. Did the cooling fans turn OFF? If so, go to step 10 . If not, go to step 7 .
  6. Remove the cooling fan 3 relay. Did the right cooling fan turn OFF? If so, go to step 11 . If not, go to step 9 .
  7. Repair the short to voltage in the left cooling fan motor supply voltage circuit. Did you complete the repair? If so, go to step 14 .
  8. Repair the short to voltage in the left cooling fan low reference circuit. Did you complete the repair? If so, go to step 14 .
  9. Repair the short to voltage in the right cooling fan motor supply voltage circuit. Did you complete the repair? If so, go to step 14 .
  10. Inspect for poor connections at the cooling fan 1 relay. Did you find and correct the condition? If so, go to step 14 . If not, go to step 12 .
  11. Inspect for poor connections at the cooling fan 3 relay. Did you find and correct the condition? If so, go to step 14 . If not, go to step 13 .
  12. Replace the cooling fan 1 relay. After repairs are complete, go to step 14 .
  13. Replace the cooling fan 3 relay. After repairs are complete, go to step 14 .
  14. Operate the system in order to verify the repair. Did you correct the condition? If so, system OK. If not, go to step 2 .

TEST B: COOLING FAN INOPERATIVE

  1. Did you perform the engine cooling diagnostic system check? If so, go to step 2 . If not, go to «DIAGNOSTIC SYSTEM CHECK (ENGINE COOLING)»(/buick/century/vi-1997-2005/remont/cooling-fan/#electric-cooling-fans__diagnostic-system-check-engine-cooling) under SELF-DIAGNOSTIC SYSTEM.
  2. Install a scan tool. Turn on the ignition, with the engine off. With a scan tool, command the fans low speed on and off. Do the low speed engine cooling fans turn on and off with each command? If so, go to step 3 . If not, go to step 4 .
  3. With a scan tool, command the fans high speed on and off. Do the high speed engine cooling fans turn on and off with each command? If so, test for intermittent and poor connections in wiring systems. If not, go to step 12 .
  4. Remove the cooling fan 1 relay. Connect a 20 Amp fused jumper between the battery positive switch side voltage circuit and the cooling fan motor supply voltage circuit of the cooling fan 1 relay. Do both cooling fans operate in low speed? If so, go to step 22 . If not, go to step 5 .
  5. Disconnect the cooling fan 2 relay. Connect the second 20 Amp fused jumper between the cooling fan low reference circuit and the cooling fan motor supply voltage circuit of the cooling fan 2 relay. Do both cooling fans operate in low speed? If so, go to step 23 . If not, go to step 6 .
  6. Connect the second 20 Amp fused jumper between the battery positive voltage circuit and the cooling fan motor supply voltage circuit of the cooling fan 2 relay. Does the right cooling fan operate in high speed? If so, go to step 9 . If not, go to step 7 .
  7. Install the cooling fan 2 relay. Disconnect the right cooling fan electrical connector. Connect the second 20 Amp fused jumper wire from the cooling fan motor supply voltage circuit to the ground circuit of the right cooling fan electrical connector. Does the left cooling fan operate in high speed? If so, go to step 25 . If not, go to step 8 .
  8. Connect the second 20 Amp fused jumper wire from the cooling fan motor supply voltage circuit of the right cooling fan electrical connector to a good ground. Does the left cooling fan operate in high speed? If so, go to step 29 . If not, go to step 30 .
  9. Install the cooling fan 2 relay. Disconnect the left cooling fan electrical connector. Connect the second 20 Amp fused jumper wire from the cooling fan motor supply voltage circuit to the cooling fan low reference circuit of the left cooling fan electrical connector. Does the right cooling fan operate in high speed? If so, go to step 26 . If not, go to step 10 .
  10. Connect the second 20 Amp fused jumper wire from the coil side battery positive voltage circuit to the cooling fan low reference circuit of the of the left cooling fan electrical connector. Does the right cooling fan operate in high speed? If so, go to step 11 . If not, go to step 31 .
  11. Probe the battery positive voltage circuit on the switch side of the cooling fan 1 relay with a test lamp that is connected to a good ground. Does the test lamp illuminate? If so, go to step 27 . If not, go to step 32 .
  12. Is the right cooling fan operating properly in high speed? If so, go to step 19 . If not, go to step 13 .
  13. Turn off the ignition. Disconnect the cooling fan 3 relay. Turn on the ignition, with the engine off. Connect a test lamp between the high speed cooling fan relay control circuit and the battery positive voltage circuit on the coil side of the cooling fan 3 relay. With a scan tool command the high speed fans on and off. Does the test lamp turn on and off with each command? If so, go to step 15 . If not, go to step 14 .
  14. Probe the battery positive voltage circuit on the coil side of the cooling fan 3 relay with a test lamp that is connected to a good ground. Does the test lamp illuminate? If so, go to step 34 . If not, go to step 33 .
  15. Install a 20 Amp fused jumper between the battery positive voltage circuit on the switch side of the cooling fan 3 relay and the cooling fan motor supply voltage circuit. Does the right cooling fan operate in high speed? If so, go to step 24 . If not, go to step 16 .
  16. Probe the battery positive voltage circuit on the switch side of the cooling fan 3 relay with a test lamp connected to a good ground. Does the test lamp illuminate? If so, go to step 17 . If not, go to step 33 .
  17. With the 20 Amp fused jumper still installed. Disconnect the right cooling fan electrical connector. Connect a test lamp from the cooling fan motor supply voltage circuit to the ground circuit of the right cooling fan electrical connector. Does the test lamp illuminate? If so, go to step 25 . If not, go to step 18
  18. Probe the cooling fan motor supply voltage circuit of the right cooling fan electrical connector with a test lamp that is connected to a good ground. Does the test lamp illuminate? If so, go to step 29 . If not, go to step 30 .
  19. Turn off the ignition. Disconnect the cooling fan 2 relay. Turn on the ignition, with the engine off. Connect a 20 Amp fused jumper between the cooling fan low reference circuit and the ground circuit of the cooling fan 2 relay. With a scan tool command the fans high speed on and off. Does the left cooling fan operate in high speed? If so, go to step 20 . If not, go to step 28 .
  20. Connect a test lamp between the high speed cooling fan relay control circuit of the cooling fan 2 relay and the battery positive voltage circuit of the cooling fan 2 relay. With a scan tool command the fans high speed on and off. Does the test lamp turn on and off with each command? If so, go to step 23 . If not, go to step 21 .
  21. Probe the battery positive voltage circuit of the cooling fan 2 relay with a test lamp that is connected to a good ground. Does the test lamp illuminate? If so, go to step 34 . If not, go to step 33 .
  22. Inspect for poor connections at the cooling fan 1 relay. Did you find and correct the condition? If so, go to step i 40 . If not, go to step 35 .
  23. Inspect for poor connections at the cooling fan 2 relay. Did you find and correct the condition? If so, go to step 40 . If not, go to step 36 .
  24. Inspect for poor connections at the cooling fan 3 relay. Did you find and correct the condition? If so, go to step 40 . If not, go to step 37 .
  25. Inspect for poor connections at the harness connector of the right cooling fan. Did you find and correct the condition? If so, go to step 40 . If not, go to step 38 .
  26. Inspect for poor connections at the harness connector of the left cooling fan. Did you find and correct the condition? If so, go to step 40 . If not, go to step 39 .
  27. Repair the left cooling fan motor supply voltage circuit for an open. Is the repair complete? If so, go to step 40 .
  28. Repair the left cooling fan ground circuit for an open. Is the repair complete? If so, go to step 40 .
  29. Repair the right cooling fan ground circuit for an open. If so, go to step 40 .
  30. Repair the right cooling fan motor supply voltage circuit for an open. Is the repair complete? If so, go to step 40 .
  31. Repair the left cooling fan low reference circuit for a short to ground or an open. Is the repair complete? If so, go to step 40 .
  32. Repair the cooling fan 1 relay battery positive voltage circuit for an open. Is the repair complete? If so, go to step 40 .
  33. Repair the battery positive voltage circuit for the cooling fan 2 and 3 relay for an open. Is the repair complete? If so, go to step 40 .
  34. Repair the high speed cooling fan relay control circuit for an open. Is the repair complete? If so, go to step 40 .
  35. Replace the cooling fan 1 relay. Is the repair complete? If so, go to step 40 .
  36. Replace the cooling fan 2 relay. Is the repair complete? If so, go to step 40 .
  37. Replace the cooling fan 3 relay. Is the repair complete? If so, go to step 40 .
  38. Replace the right cooling fan. See «COOLING FAN MOTOR»(/buick/century/vi-1997-2005/remont/cooling-fan/#electric-cooling-fans) under REMOVAL & INSTALLATION. Is the repair complete? If so, go to step 40 .
  39. Replace the left cooling fan. See «COOLING FAN MOTOR»(/buick/century/vi-1997-2005/remont/cooling-fan/#electric-cooling-fans) under REMOVAL & INSTALLATION. Is the repair complete? If so, go to step 40 .
  40. Operate the system in order to verify the repair. Did you correct the condition? If so, system OK. If not, go to step 3 .

REMOVAL & INSTALLATION

CAUTIONWhen battery is disconnected, vehicle computer and memory systems may lose memory data. Driveability problems may exist until computer systems have completed a relearn cycle. See COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION before disconnecting battery.

Note. Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. DO NOT use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

Removal

CAUTIONAn electric fan under the hood can start up even when the engine is not running and can injure you. Keep hands, clothing and tools away from any underhood electric fan.
CAUTIONTo help avoid personal injury or damage to the vehicle, a bent, cracked, or damaged fan blade or housing should always be replaced.
CAUTIONBefore servicing any electrical component, the ignition key must be in the off or lock position and all electrical loads must be off, unless instructed otherwise in these procedures. If a tool or equipment could easily come in contact with a live exposed electrical terminal, also disconnect the negative battery cable. Failure to follow these precautions may cause personal injury and/or damage to the vehicle or its components.
  1. Disconnect the negative battery cable. Disconnect the cooling fan electrical connector. (Scheme 1) Partially drain the cooling system.
  2. Remove the left hand and right hand engine mount strut braces. See ENGINE under REMOVAL & INSTALLATION in appropriate MECHANICAL article in ENGINE.
  3. Remove the left front fender upper diagonal brace. Remove the air cleaner and duct assembly.
  4. Remove the radiator inlet hose from the radiator. Remove the PCM harness from the fan shroud clip. Remove the cooling fan shroud bolts. (Scheme 2) Raise and support the vehicle.
  5. Remove the retainer from the lower left side of the fan shroud. Remove the transmission oil cooler lines from the bottom of the cooling fan shroud. Lower the vehicle. Remove the cooling fan shroud clip from the top of the radiator.
  6. Remove the upper radiator support brackets that connect to the fan shroud. (Scheme 3) Remove the fan motor heat shields. Remove the cooling fan shroud.

Scheme 1

Scheme 1
Scheme 1

Scheme 2

Scheme 2
Scheme 2

Scheme 3

Scheme 3
Scheme 3

Installation

  1. Install the cooling fan shroud. Install the cooling fan shroud clip to the top of the radiator. Apply pressure in order to completely engage the clip onto the radiator. Install the cooling fan shroud bolts. (Scheme 2) Tighten the bolts to specification. See «TORQUE SPECIFICATIONS»(/buick/century/vi-1997-2005/remont/cooling-fan/#electric-cooling-fans__torque-specifications).
  2. Raise the vehicle. Install the transmission oil cooler lines on to the retainer at the bottom of the cooling fan shroud. Install the retainer on to the lower left side of the fan shroud. Lower the vehicle.
  3. Install the fan motor heat shields. Install the upper radiator support brackets and bolts that hold the fan shroud. (Scheme 3) Tighten the bolts to specification. See «TORQUE SPECIFICATIONS»(/buick/century/vi-1997-2005/remont/cooling-fan/#electric-cooling-fans__torque-specifications).
  4. Connect the cooling fan electrical connector. (Scheme 1) Install the radiator inlet hose to the radiator. Install the air cleaner and duct assembly. Install the left front fender upper diagonal brace. Install the PCM harness on to the fan shroud clip.
  5. Install the left hand and right hand engine mount strut braces. See ENGINE under REMOVAL & INSTALLATION in appropriate MECHANICAL article in ENGINE. Fill the cooling system. Connect the negative battery cable.
CAUTIONKeep hands, tools, and clothing away from the electric engine coolant fans in order to help prevent personal injury. These fans are electric and can turn on whether or not the engine is running. The fans can start automatically with the ignition in the on position.
CAUTIONIf a fan blade is bent or damaged in any way, DO NOT repair or reuse the damaged part. Always replace a bent or damaged fan blade. Fan blades that have been damaged can not be assured of proper balance and could fail and fly apart during subsequent use. This creates an extremely dangerous situation. The fan blades must remain in proper balance. You cannot assure fan blade balance once a fan blade has been bent or damaged. A fan blade that is not in proper balance could fail and fly apart during use, creating an extremely dangerous situation.
  1. Remove the cooling fan assembly. See «COOLING FAN»(/buick/century/vi-1997-2005/remont/cooling-fan/#electric-cooling-fans). Remove the cooling fan heat shields. (Scheme 4)
  2. Disconnect the cooling fan motor electrical connectors. Remove the cooling fan blade nut. (Scheme 5) Remove the cooling fan blade.
  3. Inspect the cooling fan for bent or cracked cooling fan blades and smoothness of the cooling fan blade mating surfaces. Remove burrs or other imperfections as necessary.
  4. Remove the cooling fan motor bolts. Remove the cooling fan motor. (Scheme 6)
  5. To install the cooling fan motor, install the cooling fan motor bolts. Tighten the bolts to specification. See «TORQUE SPECIFICATIONS»(/buick/century/vi-1997-2005/remont/cooling-fan/#electric-cooling-fans__torque-specifications).
  6. Install the cooling fan blade. Install the cooling fan blade nut. Tighten the nut to specification. Connect the cooling fan motor electrical connectors.
  7. Install the cooling fan heat shields. Install the cooling fan assembly. See «COOLING FAN»(/buick/century/vi-1997-2005/remont/cooling-fan/#electric-cooling-fans).

Scheme 4

Scheme 4
Scheme 4

Scheme 5

Scheme 5
Scheme 5

Scheme 6

Scheme 6
Scheme 6

RELAY ELECTRICAL CENTER

CAUTIONAlways note the orientation of the relay. Ensure that the electrical center is secure, as not to put added stress on the wires or terminals.

Note. Required tools: Relay Puller Pliers (J 43244).

  1. Remove the electrical center cover. Locate the relay. Refer to electrical center identification views to locate the electrical center where the relay exists.
  2. Using the relay puller pliers, position the tool on opposing corners of the relay. Remove the relay from the electrical center. (Scheme 7)
  3. Install the relay in the same position as removed. Install the electrical center cover.

Scheme 7

Scheme 7
Scheme 7

TORQUE SPECIFICATIONS

ApplicationINCH Lbs. (N.m)
Electric Cooling Fan Blade Nut53 (6)
Electric Cooling Fan Motor Bolts53 (6)
Cooling Fan Shroud Bolts53 (6)
Upper Radiator Support Brackets And Bolts89 (10)

TORQUE SPECIFICATIONS

CONNECTOR IDENTIFICATION

To identify connectors (Scheme 8)and (Scheme 9).

Scheme 8

Scheme 8: CONNECTOR IDENTIFICATION
Scheme 8: CONNECTOR IDENTIFICATION

Scheme 9

Scheme 9
Scheme 9

WIRING DIAGRAMS

See appropriate SYSTEM WIRING DIAGRAMS article in WIRING DIAGRAMS.