Generator No-Load Test
WARNING: This page is about a different car, the 2004 Ford Pickup, 2004 Ford F550 Super Duty, 2004 Ford F450 Super Duty, and 2004 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.
Connect a voltmeter positive lead to B+ terminal on generator(s) and negative lead to ground. Start and run engine at 2000 RPM, with all accessories off. Read voltmeter when voltage stabilizes. Voltage should be 13.0-15.5 volts. If voltage is not as specified, repair by symptom. See SYMPTOM INDEX table under SYSTEM TESTS.