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Home >> Oldsmobile >> 1999 >> Eighty-Eight Base >> Repair and Diagnosis >> Electrical >> Charging Systems >> On-Vehicle Testing >> Battery Undercharged Or Overcharged
July 1: So it begins. Don't worry, this is not in the correct legal jurisdiction!

Battery Undercharged Or Overcharged

NOTE: Ensure battery is fully charged, terminals are clean and generator is working before testing.
  1. Turn ignition off. Disconnect generator harness connector. Turn ignition on. Check voltage between ground and Red wire in harness connector (terminal "B" on Rivera, terminal "L" on all others). If voltage is 4-14 volts, go to next step. If voltage is not 4-14 volts, go to step  4.
  2. Check for open or short on Gray wire between generator terminal "F" and PCM connector C2 terminal No. 29. Check for open or short on Red wire between generator (terminal "B" on Rivera, terminal "L" on all others) and PCM connector C2 terminal No. 61. See WIRING DIAGRAMS . Repair as necessary. If no problem is found, go to next step.
  3. Reconnect all connectors. Start engine and run at fast idle. Ensure all accessories are off. Check battery voltage. On Aurora, if voltage is not 13-16 volts, go to next step. On all others, if voltage is not 13-16 volts, go to step  8. If voltage is 13.3-15.5 volts, system is okay at this time. Check for intermittent problems.
  4. Keep engine running at fast idle. Disconnect battery thermistor connector. Check battery voltage. If voltage is 13-16 volts, go to next step. If voltage is not 13-16 volts, go to step  8.
  5. Turn ignition off. Check voltage at thermistor harness connector terminal "A" (Orange wire). If 10-15 volts exists, go to next step. If 10-15 volts does not exist, check BATT THERM fuse (10-amp) in right rear fuse block. If fuse is okay, repair open on Orange wire. If fuse is faulty, replace fuse and repair short on Orange wire. Recheck system.
  6. Disconnect generator connector. Connect a fused jumper wire from generator harness connector terminal "S" (Light Blue wire) to ground. Using an ohmmeter, check resistance between thermistor harness connector terminal "B" (Light Blue wire) and ground. If less than 5 ohms exists, go to next step. If resistance is 5 ohms or more, repair open circuit or high resistance in Light Blue wire. Recheck system.
  7. Check battery thermistor connections. Clean or repair as necessary. If no problem is found, replace battery thermistor. Recheck system.
  8. Check connections at generator connector (terminal "B" on Rivera, terminal "L" on all others) and PCM connector C2 terminal No. 35. Check for open or short to ground on Red wire. Repair as needed. If no problem is found, replace PCM. See appropriate REMOVAL & INSTALLATION article in ENGINE PERFORMANCE. Recheck charging system. See CHARGING SYSTEM CHECK .
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