Neon, 2000-2005

Alternator

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Diagnosis & Testing



Alternator Output Test
  1. Use a scan tool and check the Diagnostic Trouble Code memory to see if any DTCs exist.
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  3. Before starting the test, make sure the battery is in good condition and is fully charged. Check the conditions of the battery cables.
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  5. Perform the voltage drop test to ensure clean and tight alternator/battery electrical connections.
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  7. Be sure the alternator drive belt is properly tensioned.
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  9. A volt/amp tester equipped with both a battery lad control (carbon pile rheostat) and an inductive-type pickup clamp (ammeter probe) will be used for this test. Make sure to follows all directions supplied with the tester. If you are using a tester equipped with an inductive-type clamp, you don-t have to remove the wiring from the alternator.
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  11. Start the engine and let run until it reaches normal operating temperature, then shut the engine OFF .
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  13. Make sure all electrical accessories and lights are turned off.
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  15. Connect the volt/amp tester leads to the battery. Be sure the carbon pile rheostat control is in the OPEN or OFF position before connection the leads.
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  17. Connect the inductive camp (ammeter probe), following the instructions supplied with the test equipment.
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  19. If a volt/amp tester is not equipped with an engine tachometer, connect a separate tachometer to the engine.
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  21. Fully engage the parking brake.
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  23. Start the engine, then bring the engine speed up to 2,500 rpm.
    WARNING
    This load test must be performed within 15 seconds to prevent damage to the test equipment!

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  25. With the engine speed held at 2,500 rpm, slowly adjust the rheostat control (load) on the tester to get the highest amperage reading. Do not let the voltage drop below 12 volts. Record the reading. On certain brands of test equipment, this load will be applied automatically.
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  27. The ammeter reading must meet the minimum test amps specification which is 75 amps.
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  29. Rotate the load control to the OFF position.
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  31. Continue holding the engine speed at 2,500 rpm. If the EVR circuitry is OK, the amperage should drop below 15-20 amps. With all of the electrical accessories and vehicle lighting off, this could take several minutes of engine operation.
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  33. After procedure is complete, remove the volt/amp tester.
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Voltage Drop Test

NOTE
These tests will show the amount of voltage drop across the alternator output wire from the alternator output (B+) terminal to the battery positive post. They will also show the amount of voltage drop from the ground (-) terminal on the alternator.

A voltmeter with a 0-18 volt DC scale should be used for these tests. By repositioning the voltmeter test leads, the point of high resistance (voltage drop) can easily be found. Test points on the alternator can be reached by either removing the air cleaner housing or below by raising the vehicle.

  1. Before starting the test, make sure the battery is in good condition and is fully charged. Check the conditions of the battery cables.
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  3. Start the engine, let it warm up to normal operating temperatures, then turn the engine OFF .
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  5. Connect an engine tachometer, following the manufacturers directions.
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  7. Make sure the parking brake is fully engaged.
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  9. Start the engine, then place the blower on High, and turn the high beams interior lamps On.
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  11. Bring the engine speed up to 2,400 rpm and hold there.
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  13. To test the ground (-) circuitry, perform the following:
    1. Touch the negative lead of the voltmeter directly to the positive battery post.
    2.  
    3. Touch the positive lead of the voltmeter to the B+ output terminal stud on the alternator (NOT the terminal mounting nut). The voltage should be no higher than 0.6 volts. If the voltage is higher than 0.6 volts, touch the test lead to the terminal mounting stud nut, and then to the wiring connector. If the voltage is now below 0.6 volts, look for dirty, loose or poor connections at this point. A voltage drop test may be performed at each ground (-) connection in the circuit to locate the excessive resistance.
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  15. To test the positive (+) circuitry, perform the following:
    1. Touch the positive lead of the voltmeter directly to the negative battery post.
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    3. Touch the negative lead of the voltmeter to the ground terminal stud on the alternator case (NOT the terminal mounting nut). The voltage should be no higher than 0.3 volts. If the voltage is higher than 0.3 volts, touch the test lead to the terminal mounting stud nut, and then to the wiring connector. If the voltage is now below 0.3 volts, look for dirty, loose or poor connections at this point. A voltage drop test may be performed at each positive (+) connection in the circuit to locate the excessive resistance.
    4.  

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  17. This test can also be performed between the alternator case and the engine. If the test voltage is higher than 0.3 volts, check for corrosion at the alternator mounting points or loose alternator mounting.
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Removal & Installation



2.0L Engine
  1. Before servicing the vehicle, refer to the Precautions section.
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  3. Remove or disconnect the following:

    Negative battery cable
     
    Alternator jam nut, loosen only
     
    Alternator adjustment nut, loosen only
     
    Accessory drive splash shield
     
    Alternator lower bolt, loosen only
     
    Alternator drive belt
     
    Alternator field circuit wiring connector, push the RED locking tab to release
     
    Battery positive terminal
     
    Upper and lower bolts, move alternator off pivot bracket
     
    Pivot bracket
     
    Alternator

    Click image to see an enlarged view

    Fig. View of the alternator after removing the splash shield-2.0L engines

    View of the alternator after removing the splash shield-2.0L engines
     

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To install:

  1. Install or connect the following:

    Alternator
     
    Pivot bracket and torque the bolts to 40 ft. lbs. (54 Nm)
     
    Alternator, move it onto pivot bracket
     
    Alternator field circuit wiring connector, push RED locking tab in until it snaps in place
     
    Battery positive terminal
     
    Alternator drive belt
     
    Tension the drive belt to 100 lbs. (used) or 135 lbs. (new)
     
    Alternator adjustment bolt
     
    Alternator jam nut and torque nut to 40 ft. lbs. (54 Nm)
     
    Alternator mount bolts and torque the bolts to 40 ft. lbs. (54 Nm)
     
    Accessory drive splash shield
     
    Negative battery cable
     

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