GM Grand Am/Achieva/Calais/Skylark/Somerset 1985-98

Alternator

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TESTING



The battery must be fully charged condition before attempting and charging system testing procedures.

  1. Check the drive belt and wiring.
  2.  
  3. On models with an indicator light, turn the ignition switch ON . With the engine stopped the light should illuminate. If not, detach the harness at the alternator and ground L terminal.
    1. If the lamp illuminates, repair or replace the alternator.
    2.  
    3. If the lamp does not light up, locator the open circuit between the ignition switch and grounding lead. The lamp may be open.
    4.  

  4.  
  5. With the ignition switch ON , engine running at moderate speed, the lamp should be off. If not, detach the wiring harness at the alternator.
    1. If the lamp stays on, check for grounded L terminal wire at the alternator.
    2.  
    3. If the lamp goes off, replace or repair the alternator.
    4.  

  6.  
  7. If the battery is undercharged or overcharged.
    1. Detach the electrical wiring from the alternator.
    2.  
    3. With the ignition switch ON , the engine not running, connect a voltmeter to ground to terminal L in the harness.
    4.  
    5. A zero reading indicates and open circuit between the terminal and battery. Correct the problem.
    6.  
    7. Reconnect the harness to the alternator, start and run the engine at moderate speed.
    8.  
    9. Measure the voltage across the battery. If it is above 16 volts, check the S terminal circuit if used for high resistance or an intermediate connection. Clean and tighten all connection., If the alternator still operates above 16 volts, replace it.
    10.  
    11. Place a current clamp around the alternator output lead and turn on the accessories, load the battery and obtain maximum amperage. Maintain this voltage at 13 volts or more.

      If within 15 amps or rated output, the alternator is OK.
       
      If not within 156 amps of rated output, replace the alternator.
       

    12.  

  8.  

REMOVAL & INSTALLATION



Except 2.3L (VIN A, D and 3)

See Figures 1, 2 and 3

  1. Disconnect the negative battery cable.
  2.  
  3. Label and disengage the electrical connections from the alternator.
  4.  
  5. On the 2.5L engines, loosen the adjusting bolts and remove the alternator belt.
  6.  
  7. If equipped with a serpentine belt, loosen the tensioner and turn it counterclockwise to remove the belt.
  8.  
  9. Unfasten the alternator mounting bolts, then detach the alternator air inlet connector (3.1L engine only) and remove the alternator from the engine.
  10.  



Click image to see an enlarged view

Fig. Fig. 1: After removing the belt and detaching the electrical connections, unfasten the front retaining bolts



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Fig. Fig. 2: Now unfasten the rear mounting bolts and remove the alternator from the vehicle

To install:
  1. Fasten the alternator to the mounting bracket, using the retaining bolts, washers and nuts. Tighten the retainers to the specifications listed in the accompanying figures.
  2.  



Click image to see an enlarged view

Fig. Fig. 3: Position the alternator bracket on the engine and secure if removed-2.4L engine shown

  1. If equipped with the 3.1L engine, attach the alternator air inlet connector.
  2.  
  3. Install the serpentine or alternator belt, as applicable. For details, please refer to Routine Maintenance of this information.
  4.  
  5. Engage the alternator electrical connections. Tighten the "Bat" terminal nut to 65 inch lbs. (7 Nm).
  6.  
  7. Check the belt tension, then adjust if necessary.
  8.  
  9. Connect the negative battery cable, then check the alternator for proper operation.
  10.  

2.3L (VIN A, D and 3) Engines
1988-90 VEHICLES

See Figures 4 and 5

  1. Disconnect the negative battery cable.
  2.  

To avoid personal injury when rotating the serpentine belt tensioner, use a tight fitting 13mm wrench that is at least 24 inch (61cm) long. Tool J 37059 can also be used to do this.

  1. Loosen the tensioner pulley bolt, turn the pulley counterclockwise and remove the serpentine belt from the alternator pulley.
  2.  
  3. Tag and disconnect the two vacuum lines at the front of the engine.
  4.  
  5. Remove the vacuum harness retaining bracket, then position the harness aside.
  6.  
  7. Detach the injector harness, alternator connector and the battery lead from the alternator. Position the harness out of the way.
  8.  



Click image to see an enlarged view

Fig. Fig. 4: 1990 2.3L engine alternator mounting-without A/C



Click image to see an enlarged view

Fig. Fig. 5: 2.3L engine alternator mounting-with A/C

  1. Unfasten and remove the two rear alternator mounting bolts.
  2.  
  3. Remove the front alternator bolt and the engine harness clip.
  4.  
  5. Remove the alternator from the vehicle between the engine lifting eyelet and the A/C compressor and condenser hose, to the right (passenger) side of the radiator filler neck.
  6.  

To install:
  1. Position the alternator in the vehicle, then install and hand-tighten the front mounting bolt and the engine harness clip.
  2.  
  3. Install the two rear mounting bolts, then tighten them to 19 ft. lbs. (26 Nm).
  4.  
  5. Tighten the front alternator bolt to 37 ft. lbs. (50 Nm).
  6.  
  7. Install the serpentine belt. For details, please refer to Routine Maintenance of this information guide.
  8.  
  9. Attach the injector harness wiring, alternator connector and the alternator battery lead.
  10.  
  11. Install the vacuum harness and the retaining clip.
  12.  
  13. Connect the two hoses to the vacuum harness as tagged during removal, then connect the negative battery cable.
  14.  

1991-95 VEHICLES
  1. Disconnect the negative battery cable at the battery.
  2.  

To avoid personal injury when rotating the serpentine belt tensioner, use a tight fitting 13mm wrench that is at least 24 inch (61cm) long. Tool J 37059 can also be used to do this.

  1. Loosen the tensioner pulley bolt, turn the pulley counterclockwise and remove the serpentine belt from the alternator pulley.
  2.  
  3. Label and disconnect the oil/air separator hose and the vacuum harness at the front of the engine.
  4.  

When removing and installing the lower alternator mounting bolts, shield the radiator core from possible tool damage to the fins and tubes.

  1. Unfasten the lower alternator bolts located at the rear of the alternator. There is one 13mm head hex sized bolt and one 10mm hex head sized bolt.
  2.  
  3. Remove the upper alternator bolt.
  4.  
  5. Partially remove the alternator, then detach the alternator electrical connector and battery lead, and remove the alternator from the vehicle.
  6.  

To install:
  1. Position the alternator into the engine compartment, then attach the electrical connector and battery lead.
  2.  
  3. Install and hand-tighten the upper retaining bolt.
  4.  
  5. Install the two lower (rear) alternator mounting bolts. Tighten the bolts to 19 ft. lbs. (26 Nm)
  6.  
  7. Tighten the upper (front) alternator bolt to 37 ft. lbs. (50 Nm).
  8.  
  9. Install the serpentine belt. For details, please refer to Routine Maintenance of this information.
  10.  
  11. Connect the oil/air separator hose and the vacuum harness as tagged during removal.
  12.  
  13. Connect the negative battery cable at the battery.
  14.  

 
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