Generator No-Load Test
WARNING: This page does not describe the selected car, but rather 9 other vehicles, including the 2003 Ford Pickup, 2003 Ford F550 Super Duty, 2003 Ford F450 Super Duty, 2003 Ford Excursion, and 2003 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.
Switch tester to voltmeter function. Connect voltmeter positive lead to B+ terminal on generator and negative lead to ground. Turn all electrical accessories off. Start and run engine up to 2000 RPM. Read voltmeter when voltage stabilizes. Voltage should be 13-15 volts. If voltage is not as specified, repair by symptom. See SYMPTOM INDEX table under SYSTEM TESTS.