DCS Troubleshooting: Alternator Not Charging

Alternator inputs and outputs

  • Use a multimeter to verify system voltage. A charged battery should be around 12.6 volts. With the engine running and the alternator excited, the system should read around 14 volts.
  • If you have the correct voltage, a load test can be performed on the alternator. This can typically be done at your local auto parts store.
  • Verify the B+ cable from the battery to the alternator is securely connected. This connection is typically made using the existing wiring your vehicle came with.
  • To reduce parasitic loads on the starting system, a PCM will disable the alternator during cranking. The PCM reads the tachometer signal and will allow the charging system to operate after verifying the engine is running via tachometer input. A/C compressors will not operate due to the same reason.

If issues continue to persist, you may contact us for more troubleshooting tips: 320-440-2900.

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