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    2005 Mercedes Benz CL65 AMG 6.0L SFI Twin Turbo 12cyl

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    ISUZU Amigo/Pick-ups/Rodeo/Trooper 1981-1996

    Alternator

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    TESTING



    A charge indicator lamp is used in most vehicles to signal when there is a fault in the charging system. This lamp is located in the gauge package and is used in diagnosis. A voltmeter may be used instead of the charge indicator lamp in diagnosis.

    Before performing any alternator tests, check the drive belt(s) for wear and tension. Also check the wiring for obvious damage. Make all needed repair before proceeding.

    4-Cylinder Models With External Voltage Regulator

    See Figures 1, 2 and 3



    Click image to see an enlarged view

    Fig. Fig. 1: Checking continuity between the slip rings



    Click image to see an enlarged view

    Fig. Fig. 2: Check the continuity between the slip ring and rotor core



    Click image to see an enlarged view

    Fig. Fig. 3: Checking the stator resistance

    1. Remove the alternator from the vehicle and place on a clean work surface.
    2.  
    3. Remove the alternator through-bolts and front cover.
    4.  
    5. Remove the shaft nut, pulley and fan.
    6.  
    7. Remove the cover and front bearing.
    8.  
    9. Remove the rear cover and stator assembly.
    10.  
    11. Remove the brush and diode assembly.
    12.  
    13. Test the rotor for an open circuit by measuring the resistance between the slip rings. The normal resistance is 4 ohms.
    14.  
    15. Check the resistance between the rotor core and the positive side of the slip ring. The resistance should be 1 milo-ohm or above.
    16.  
    17. Make a continuity test across the stator coil. There should be continuity.
    18.  
    19. Check the resistance between the stator coils and the core using an ohmmeter. The resistance should be 1 milo-ohm.
    20.  
    21. Measure the resistance between each diode terminal and holder in forward and reverse direction with an ohmmeter. The resistance should be nearly zero in one direction and infinite in the other.
    22.  

    4-Cylinder Models With Internal Voltage Regulator
    CHARGING CIRCUIT CHECK

    See Figure 4



    Click image to see an enlarged view

    Fig. Fig. 4: Charging system check with the alternator installed on the vehicle

    This procedure must be done with the alternator installed, and the battery fully charged.

    1. Disconnect the wire from the battery terminal at the alternator, and connect it to the negative terminal of a circuit tester (ammeter).
    2.  
    3. Connect the positive lead of the ammeter to the battery terminal of the alternator.
    4.  
    5. Run the engine from idle to 2000 rpm. The standard amperage should be less than 10 amps.
    6.  
    7. If the reading is higher, replace the voltage regulator.
    8.  
    9. Connect the positive lead of the voltmeter to the battery terminal of the alternator, and the negative lead to ground. Run the engine at 2000 rpm. The standard voltage should be 14.2-14.8 volts.
    10.  
    11. If the reading is higher, replace the voltage regulator.
    12.  
    13. If the reading is lower, check the regulator and alternator internal components.
    14.  
    15. Ground the F (field) terminal of the regulator.
    16.  
    17. Start the engine and check the voltage reading of the battery terminal of the alternator.
    18.  
    19. If the voltage reading is higher than specified, replace the regulator. If not, inspect the alternator.
    20.  

    INTERNAL COMPONENT CHECK
    1. Remove the alternator from the vehicle and place on a clean work surface.
    2.  
    3. Remove the long through-bolts.
    4.  
    5. Remove the pulley nut and pulley.
    6.  
    7. Remove the rotor assembly, bearing retainer and front bearing.
    8.  
    9. Remove the front cover and rectifier retaining nuts.
    10.  
    11. Remove the rear cover, stator assembly and nuts.
    12.  
    13. Remove the fan guide, battery terminal and condenser.
    14.  
    15. Remove the diode assembly and brush/regulator assembly.
    16.  
    17. Test the rotor for an open circuit by measuring the resistance between the slip rings. The normal resistance is 2.63 ohms or less.
    18.  
    19. Check the resistance between the rotor core and the positive side of the slip ring. The resistance should be 1 milo-ohm or above.
    20.  
    21. Make a continuity test across the stator coil. There should be continuity.
    22.  
    23. Check the resistance between the stator coils and the core using an ohmmeter. The resistance should be 1 milo-ohm or more.
    24.  
    25. Measure the resistance between each diode terminal and holder in forward and reverse direction with an ohmmeter. The resistance should be nearly zero in one direction and infinite in the other.
    26.  
    27. Repair any faulty components and reassemble, or replace the alternator if necessary.
    28.  

    V6 Engines
    INTERNAL COMPONENT CHECK
    1. Remove the alternator from the vehicle and install in a test stand.
    2.  
    3. Make the alternator connections according to the manufacturer's instructions, but leave the carbon pile disconnected. The battery must be fully charged.
    4.  
    5. Slowly increase the alternator speed and observe the voltage.
    6.  
    7. If the voltage is uncontrolled and increases above 16.0 volts, then the rotor field is shorted or grounded, the regulator is defective, or both. A defective rotor field coil can cause the regulator to become defective.
    8.  
    9. If the voltage is below 16.0 volts, increase the speed and adjust the carbon pile to obtain the maximum amperage output. Maintain a voltage above 13.0 volts.
    10.  
    11. If the output is within 15 amperes of the rated output, the alternator is good. If the output is not within 15 amperes of rated output, the alternator is defective and requires replacement. The V6 equipped alternator is not serviceable.
    12.  

    CHARGING CIRCUIT CHECK

    See Figure 5



    Click image to see an enlarged view

    Fig. Fig. 5: Checking the alternator on V6 models

    1. With the ignition switch ON and the engine stopped, the alternator dash lamp should be ON. If not, detach the wiring harness at the generator and ground the L'' terminal lead.
    2.  
    3. If the lamp illuminates, replace the alternator. If the lamp does not illuminate, locate the open circuit between the grounding lead and the ignition switch. Check the lamp, it may be open.
    4.  
    5. With the ignition switch ON and the engine running at moderate speed, the dash lamp should be OFF. If not, stop the engine, then turn the switch ON and detach the wiring harness at the alternator.
    6.  
    7. If the lamp goes out, replace the alternator. If the lamp stays ON, check for a grounded L'' terminal wire in the alternator wire harness.
    8.  
    9. Determine if the battery is undercharged or overcharged.

      An undercharged battery is evidenced by slow cranking or a dark hydrometer.
       
      An overcharged battery is evidenced by excessive spewing of electrolyte from the vents.
       

    10.  
    11. Detach the wiring harness connector from the alternator.
    12.  
    13. With the ignition switch ON , and the engine not running, connect a voltmeter from ground to the L'' terminal in the wiring harness, and to the I'' terminal, if used.
    14.  
    15. A zero reading indicates an open circuit between the terminal and the battery. Repair the circuit as necessary.
    16.  
    17. Connect the harness connector to the alternator and run the engine at moderate speed with all accessories OFF .
    18.  
    19. Measure the voltage across the battery. If above 16 volts, replace the alternator.
    20.  
    21. Connect an ammeter at the alternator output terminal, run the engine at moderate speed, turn ON all the accessories and load the battery with a carbon pile to obtain maximum amperage. Maintain voltage at 13 volts or above.
    22.  
    23. If the output is within 15 amps of the rated output of the alternator (stamped on the alternator case), the alternator is good. If the output is not within 15 amps, replace the alternator.
    24.  

    REMOVAL & INSTALLATION



    1981-85 Vehicles

    See Figure 6



    Click image to see an enlarged view

    Fig. Fig. 6: Alternator and components-1981-85 engines

    1. Disconnect the negative battery cable.
    2.  
    3. If equipped with an air pump, remove it for additional working space.
    4.  
    5. Disconnect and label the alternator wiring.
    6.  
    7. Remove the alternator pivot bolt on the lower part of the alternator. Remove the drive belt from the pulley.
    8.  
    9. Remove the alternator mounting bolt(s) and the alternator from the engine.
    10.  

    To install:
    1. Install the alternator.
    2.  
    3. Adjust the belt tension and tighten the alternator mounting bolts.
    4.  
    5. Connect the alternator wiring.
    6.  
    7. Connect the negative battery cable.
    8.  
    9. Start the vehicle and check for proper voltage output.
    10.  

    1986-96 Models With V-Belts

    See Figures 7, 8, 9 and 10



    Click image to see an enlarged view

    Fig. Fig. 7: Alternator installation-1986-96 2.3L and 2.6L engines



    Click image to see an enlarged view

    Fig. Fig. 8: Alternator and components-2.3L and 2.6L engines



    Click image to see an enlarged view

    Fig. Fig. 9: Alternator installation-2.2L engine



    Click image to see an enlarged view

    Fig. Fig. 10: Alternator bracket and hardware-2.2L engine

    1. Disconnect the negative battery cable.
    2.  
    3. Remove the terminal plug and the battery lead from the rear of the alternator.
    4.  
    5. Loosen the alternator pivot and retainer bolts.
    6.  
    7. Remove the drive belt.
    8.  
    9. Remove the air pump bracket bolt from the rear of the alternator, if equipped.
    10.  
    11. Remove the pivot bolts and bracket from the front of the alternator, then remove the lower alternator retainer nut and bolt.
    12.  
    13. Remove the alternator from the vehicle.
    14.  

    To install:
    1. Position the alternator to the bracket on the engine.
    2.  
    3. Install the lower retainer nut and bolt. Attach the adjusting bracket and pivot bolts.
    4.  
    5. Install the air pump bracket, if removed.
    6.  
    7. Install the drive belt.
    8.  
    9. Tension the drive belt.
    10.  
    11. Tighten the lower mounting bolt to 26 ft. lbs. (35 Nm), and the pivot bolts to 18 ft. lbs. (25 Nm).
    12.  
    13. Tighten the air pump bracket bolt to 18 ft. lbs. (25 Nm).
    14.  
    15. Connect the alternator terminal wires.
    16.  
    17. Connector the battery lead wire to the rear of the alternator.
    18.  
    19. Connect the negative battery cable.
    20.  
    21. Start the vehicle and check for proper alternator operation.
    22.  

    V6 Engines With Serpentine Belt

    See Figures 11, 12, 13, 14, 15 and 16



    Click image to see an enlarged view

    Fig. Fig. 11: Unfasten the control harness from the rear of the alternator assembly-1991 Trooper



    Click image to see an enlarged view

    Fig. Fig. 12: Remove the protective plate over the main power connection



    Click image to see an enlarged view

    Fig. Fig. 13: Loosen and remove the upper adjusting bolt



    Click image to see an enlarged view

    Fig. Fig. 14: After the lower retainer bolt has been removed, lift out the alternator assembly



    Click image to see an enlarged view

    Fig. Fig. 15: V6 alternator installation



    Click image to see an enlarged view

    Fig. Fig. 16: V6 alternator and components

    1. Disconnect the negative battery cable.
    2.  
    3. Remove the serpentine belt.
    4.  
    5. Raise and support the front of the vehicle.
    6.  
    7. Remove the right front tire and wheel assembly for access through the wheelwell.
    8.  
    9. Working through the wheelwell, remove the alternator bracket-to-block bolt, then remove the brace-to-intake nut.
    10.  
    11. Unfasten the alternator wiring connector, then remove the battery terminal nut and wire.
    12.  
    13. Loosen the alternator retaining bolts, then support the alternator and remove the fasteners. Remove the alternator from the vehicle.
    14.  

    To install:
    1. Position the alternator in the vehicle and loosely install the retaining bolts.
    2.  
    3. Tighten the left alternator bolt to 22 ft. lbs. (30 Nm) and the right bolt to 32 ft. lbs. (43 Nm).
    4.  
    5. Install the battery terminal wire and tighten the retaining nut, then engage the alternator wiring connector.
    6.  
    7. Install the alternator brace, then tighten the retaining nuts and bolts to 22 ft. lbs. (30 Nm).
    8.  
    9. Hold the serpentine drive belt tensioner, back off the belt while slipping the belt over the alternator pulley. Gradually lower the tensioner into contact with the belt, then check for proper alignment and tension.
    10.  
    11. Install the wheel and tire assembly. Lower the vehicle.
    12.  
    13. Connect the negative battery cable.
    14.  
    15. Start the vehicle and check for proper alternator operation.
    16.  

     
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