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Alternator Relay

  1. Testing information for relay internals is not available from manufacturer. If there is an interruption in charging system warning light circuit, alternator relay functions as a back-up for electrical flow from ignition switch.
  2. To test warning light circuit operation, perform following test. Connect voltmeter to battery. Start engine and note voltmeter reading. Charging system voltage should be 13-15 volts. If charging system voltage is not as indicated, go to step 4). Locate and remove alternator relay from engine compartment relay box. See Fig 1.
  3. With relay removed, if voltmeter still indicates charging voltage between 13-15 volts, warning light circuit is good. If voltmeter indicates battery voltage, repair warning light circuit as required. See Figure.
  4. If charging voltage is not as indicated, check alternator 2-terminal connector (Black/White wire) for battery voltage when ignition switch is in RUN position. If battery voltage does not exist at Black/White wire terminal with relay installed in engine compartment relay box connector, check for open in circuit from ignition switch to alternator. See Figure.
Fig 1: Locating Alternator Relay
G92B03645Courtesy of CHRYSLER CORP.