Test B: Warning Indicator On, System Is Not Charging

1. Measure voltage of Black/Orange wire at generator B+ terminal. If battery voltage is present, go to next step. If battery voltage is not present, repair open in Black/Orange wire. See WIRING DIAGRAMS . Retest system operation.
2. Disconnect generator 3-pin connector. Measure voltage of Yellow/White wire at generator connector terminal "A". See Fig 1. If battery voltage is present, go to next step. If battery voltage is not present, repair open in Yellow/White wire between generator and battery junction box. See WIRING DIAGRAMS . Retest system operation.
3. Start engine. Measure voltage of Light Green/Red wire at generator connector terminal "I". If battery voltage is present, go to next step. If battery voltage is not present, repair open in Light Green/Red wire between generator and instrument panel. See WIRING DIAGRAMS . Retest system operation.
4. Start engine. With engine running, turn headlights and rear defogger on, and turn blower motor to high speed. Increase engine speed to 2000 RPM, and measure voltage drop in Black/Orange wire between generator terminal B+ terminal and positive battery terminal. If voltage drop is less than .5 volt, replace generator. See GENERATOR  under REMOVAL & INSTALLATION. If voltage drop is greater than .5 volt, repair high resistance in Black/Orange wire between generator and battery junction box. See WIRING DIAGRAMS . Retest system operation.

Fig 1: Identifying Generator 3-Pin Connector Terminals

Courtesy of FORD MOTOR CO.