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Regulator Circuit "S" Testing

  1. Disconnect wiring harness connector from regulator. Connect a jumper wire between regulator terminal "A" and terminal "A" of wiring harness connector. Connect a jumper wire between regulator terminal "F" screw head and ground on alternator rear housing. See Fig 1.
    Fig 1: Testing Regulator Circuit "S"
    G91E13429Courtesy of FORD MOTOR CO.
  2. Start engine and allow to idle. Connect voltmeter negative lead to ground. Connect voltmeter positive lead to terminal "S" and then to terminal "I" of wiring harness connector. See Fig 1. The voltage at terminal "S" should be approximately one-half the voltage at terminal "I". If voltage readings are normal, remove jumper wires and replace regulator. Rerun LOAD ON-VEHICLE TESTING.
  3. If voltage is not present, remove jumper wires and repair faulty wiring circuit in alternator. Reconnect regulator harness connector and rerun LOAD ON-VEHICLE TESTING to confirm repair.
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