Test B: Warning Indicator Is On With Engine Running, System Is Not Charging
WARNING: This page is about a different car, the 2004 Ford Ranger. However, it is still accessible from the selected car via links, so may be relevant.
- Check Generator B+ Circuit (Black/Orange Wire)
Measure voltage between ground and generator terminal B+ (Black/Orange wire). See Figure. Is the voltage equal to battery voltage? If yes, go to next step. If no, repair Black/Orange wire between generator and battery junction box. See WIRING DIAGRAMS . - Check "A" Circuit (Yellow/White Wire)
Disconnect generator 3-pin harness connector. Measure voltage between ground and generator harness connector terminal No. 3 (Yellow/White wire). See Fig 1 or Fig 2 . Is the voltage equal to battery voltage? If yes, go to next step. If no, repair Yellow/White wire between battery and generator. See WIRING DIAGRAMS . - Check "I" Circuit (Light Green/Red Wire) For An Open
Turn ignition on. Measure voltage between ground and generator harness connector terminal No. 1 (Light Green/Red wire). See Fig 1 or Fig 2 . Is the voltage equal to battery voltage? If yes, go to next step. If no, repair Light Green/Red wire between generator connector and instrument cluster. See WIRING DIAGRAMS . - Check For Voltage Drop In B+ Circuit (Black/Orange Wire)
Turn ignition off. Connect generator 3-pin harness connector. Start engine and let idle. With the engine running, turn the headlamps on and the blower motor to the high position. With the engine at 2000 RPM, measure the voltage drop between the generator B+ terminal (Black/Orange wire) and the positive battery terminal. See Figure. Is the voltage drop less than 0.5 volt? If yes, for 2.3L engine, replace generator. See GENERATOR under REMOVAL & INSTALLATION. For 3.0L and 4.0L engines, go to next step. If no, repair Black/Orange wire between generator and battery. See WIRING DIAGRAMS . - Check Generator Integrity
With the engine running at approximately 2000 RPM, full field the generator by grounding the "F" (field) terminal on the voltage regulator. See Figure. Did the charging system achieve approximately 75 percent of full output? If yes, install a new voltage regulator. See VOLTAGE REGULATOR under REMOVAL & INSTALLATION. Test the system for normal operation. If no, install a new generator. See GENERATOR under REMOVAL & INSTALLATION. Test the system for normal operation.