Generator Warning Light

NOTE: For vehicles without a charge warning light, see UNDERCHARGED OR OVERCHARGED BATTERY TEST .

Check belt and wiring. Ensure battery is fully charged and main fusible link is okay. Turn ignition on with engine off. Ensure generator charge indicator light comes on. If charge indicator light comes on, go to step 3). If charge indicator light does not come on, go to next step.
Unplug generator connector. Using a jumper wire, connect "L" terminal (harness side) to ground. See Fig 1. If charge indicator light comes on, repair or replace alternator. If charge indicator light does not come on, locate open in "L" terminal circuit between generator connector and ignition switch.
Start engine and allow it to idle. If charge indicator light stays on, go to step 4). If charge indicator light flickers on and off, check positive alternator diodes. If charge indicator light goes off, go to step 5).

Fig 1: Identifying Alternator Connector Terminals
Courtesy of ISUZU MOTOR CO.
Turn ignition off. Disconnect generator connector. Start engine and run at moderate speed. If charge indicator light remains on, check for short to ground in "L" terminal circuit. If charge indicator light goes off, replace or repair alternator.