1988 Buick Skyhawk Base, 4D Wagon, AutomaticFACTORY OEM SERVICE PROCEDURE

Cs Series Bench Tests

  1. Mount alternator on a test stand. Make connections as shown in charging system wiring diagram. See Figure. Leave carbon pile disconnected. Ground polarity of alternator and battery must be the same. Ensure battery is fully charged. Use a 30-500 ohm resistor between battery and terminal "L".
  2. Slowly increase alternator speed and observe voltage. If voltage is uncontrolled and increases to more than 16 volts, rotor field is shorted and/or regulator is defective. A shorted rotor field coil can cause the regulator to become defective.
  3. If voltage is less than 16 volts, increase speed and adjust carbon pile to obtain maximum amperage output. If output is within 15 amperes of rated output, alternator is okay. If output is not within 15 amperes of rated output, replace alternator.
Fig 1: Exploded View of 10SI Alternator
G774
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Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

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