Delco Remy CS130 & CS121 Series Alternator Repair Manual, Page 3

TROUBLE SHOOTING

A basic wiring diagram is shown in Figures 3 and 3A (above). When operating normally, the indicator bulb will come on when the switch is turned on, and will then go out when the engine starts. If the indicator operates abnormally, or if an under-charged or overcharged battery condition occurs, the following procedure may be used to diagnose the charging system. Remember that an undercharged battery is often caused by accessories being left on over-night, or by a defective switch which allows a bulb, such as a trunk or glove box light, to stay on. This alternator does not have a regulator by-pass test hole.