Other Ford Models battery warning light

PRELIMINARY INSPECTION
Ensure connections at generator, regulator and engine ground are clean and tight.
Turn ignition on and ensure charge warning light operates. Check bulb and circuit, if necessary. Start engine and verify charge warning light goes out.
Ensure battery posts and cables are clean and tight.
Inspect drive belt.
Inspect battery junction box fuse No.11 (20-amp) and central junction box fuse No. 30 (30-amp).
Inspect Gray fusible links located near starter motor relay.
Check all connections for looseness or corrosion.
If fault is found, repair as necessary. If no fault is found, repair by symptom. See SYMPTOM INDEX under SYSTEM TESTS.

TEST C: WARNING INDICATOR IS ON WITH ENGINE RUNNING, SYSTEM IS CHARGING
Disconnect generator 3-pin connector. Turn ignition on and observe warning indicator. If warning indicator illuminates, repair short to ground in Light Green/Red wire between generator and instrument panel. On Lightning models, if warning indicator does not illuminate, replace generator. See GENERATOR under REMOVAL & INSTALLATION. On all other models, go to next step.
NOTE:Generator 1-pin connector "S" terminal is not accessible on Lightning 5.4L 2V, when mounted on engine.

With engine running at 2000 RPM, measure voltage at generator 1-pin connector terminal "S" (component side). See Fig. 1. If voltage is 5 volts or greater, replace voltage regulator. See VOLTAGE REGULATOR under REMOVAL & INSTALLATION. If voltage is less than 5 volts, replace generator. See GENERATOR under REMOVAL & INSTALLATION.