GM S-Series Pick-ups and SUV's 1994-1999 Repair Guide

Alternator

Print

TESTING



See Figure 1



Click image to see an enlarged view

Fig. Fig. 1: Proper connections for alternator testing

  1. Check drive belt(s) for wear and tension. Check wiring for obvious damage.
  2.  
  3. Go to Step 7 for vehicles without a charge indicator lamp.
  4.  
  5. With the ignition switch ON and the engine stopped, the lamp should be ON. If not, detach the wiring harness at the generator and ground the "L'' terminal lead.
  6.  
  7. 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.
  8.  
  9. With the ignition switch ON and the engine running at moderate speed, the lamp should be OFF. If not, stop the engine, then turn the switch ON and detach the wiring harness at the alternator.
  10.  
  11. If the lamp goes out, replace the alternator. If the lamp stays ON, check for a grounded "L'' terminal wire in the harness.
  12.  
  13. 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.
     

  14.  
  15. Detach the wiring harness connector from the alternator.
  16.  
  17. 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.
  18.  
  19. A zero reading indicates an open circuit between the terminal and the battery. Repair the circuit as necessary.
  20.  
  21. Attach the harness connector to the alternator and run the engine at moderate speed with accessories OFF.
  22.  
  23. Measure the voltage across the battery. If above 16 volts, replace the alternator.
  24.  
  25. 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.
  26.  
  27. 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.
  28.  

REMOVAL & INSTALLATION



Except 2.2L Engine

See Figures 2 through 7



Click image to see an enlarged view

Fig. Fig. 2: Remove the air inlet duct assembly



Click image to see an enlarged view

Fig. Fig. 3: Unfasten the nut retaining the radiator hose brace to the back on the alternator



Click image to see an enlarged view

Fig. Fig. 4: Remove the electrical wire from the rear of the alternator, ...



Click image to see an enlarged view

Fig. Fig. 5: ... then remove the alternator's mounting bolts ...



Click image to see an enlarged view

Fig. Fig. 6: ... and remove the alternator from the vehicle



Click image to see an enlarged view

Fig. Fig. 7: Alternator mounting-4.3L engine

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the air inlet duct assembly, if necessary.
  4.  
  5. Carefully relieve the serpentine drive belt tension, then remove the belt from the alternator pulley. Do not allow the tensioner to snap back into position once the belt is off the pulley.
  6.  
  7. Remove the nut retaining the radiator hose brace to the back on the alternator.
  8.  
  9. If equipped, unfasten the retainers, then remove the brace from the engine and/or the alternator.
  10.  
  11. Disconnect the battery terminal boot wiring from the back of the alternator, then unplug the regulator wiring connector.
  12.  
  13. Support the alternator and remove the mounting bolts (usually 2) from either side of the alternator, then remove the alternator from the vehicle.
  14.  

To install:
  1. Position the alternator in the vehicle and loosely install using the mounting bolts.
  2.  
  3. If equipped, loosely install the brace to the engine and/or alternator.
  4.  
  5. Tighten the left or front alternator retaining bolts to 36 ft. lbs. (50 Nm), the right or rear alternator bolt to 18 ft. lbs. (25 Nm), the brace bolt to 18 ft. lbs. (25 Nm) and/or the brace nut to 22 ft. lbs. (30 Nm), as applicable.
  6.  
  7. Connect and secure the alternator wiring.
  8.  
  9. Carefully relieve the serpentine drive belt tension and position the belt over the alternator pulley, then slowly release the tensioner into position.
  10.  
  11. If equipped, install the air inlet duct assembly.
  12.  
  13. Connect the negative battery cable.
  14.  

2.2L Engine

See Figures 8 through 12



Click image to see an enlarged view

Fig. Fig. 8: Alternator mounting-2.2L engine

  1. Disconnect the negative battery cable.
  2.  
  3. Raise and support the front of the vehicle, then remove the passenger side tire and wheel assembly for access to the rear of the alternator through the wheel well.
  4.  
  5. Working through the wheel well, unfasten the alternator brace-to-block bolt, then remove the brace-to-intake nut and the brace-to-engine stud nut.
  6.  
  7. Unplug the alternator wiring connector, then remove the battery terminal nut and wire.
  8.  
  9. Carefully release the serpentine belt tension and remove the belt from the alternator pulley. Do not allow the tensioner to snap back into position once the belt is off the pulley.
  10.  
  11. Loosen the alternator retaining bolts, then support the alternator and remove the fasteners. Remove the alternator from the vehicle.
  12.  



Click image to see an enlarged view

Fig. Fig. 9: The alternator brace-to-block bolts and wires are accessible through the passenger side wheel well



Click image to see an enlarged view

Fig. Fig. 10: After unfastening all the retainers, remove the brace through the opening



Click image to see an enlarged view

Fig. Fig. 11: The top bolt (1) is removed first from the rear of the alternator and is accessible through the wheel well opening, then remove the bottom mounting bolt (2) from the front



Click image to see an enlarged view

Fig. Fig. 12: After the bolts are unfastened, remove the alternator from the engine compartment

To install:
  1. Position the alternator in the vehicle and loosely install the retaining bolts.
  2.  
  3. On 1994-98 models, tighten the top alternator bolt to 22 ft. lbs. (30 Nm) and the bottom bolt to 32 ft. lbs. (43 Nm).
  4.  
  5. On 1999-99 models, tighten the rear bolt to 37 ft. lbs. (50 Nm) and the front bolt to 18 ft. lbs. (25 Nm).
  6.  
  7. On 1994-98 models, install the alternator brace, then tighten the retaining nut(s) and bolts to 22 ft. lbs. (30 Nm).
  8.  
  9. On 1999-99 models, install the alternator brace, tighten the brace-to-alternator and brace-to-intake retainers to 18 ft. lbs. (25 Nm). Tighten the brace-to-engine stud nut to 37 ft. lbs. (50 Nm).
  10.  
  11. Install the battery terminal wire and tighten the retaining nut, then engage the alternator wiring connector.
  12.  
  13. 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.
  14.  
  15. Connect the negative battery cable.
  16.  

 
label.common.footer.alt.autozoneLogo