Charging System The Charging Circuit The charging circuit contains. . , I 12-volt battery I alternator I voltage regulator How the Circuit Works I The battery supplies starting voltage. I The alternator supplies power to operate the vehicle and to recharge the battery. The voltage regulator responds to alternator output and battery condition (charge) and meter's altemator output to charge the battery as required Trouble-Shooting Procedures Charging system conditions include . . i I dead battery ' I battery using water excessively I alternator warning light that doesn't light I alternator warning light that doesn't go out. Charging system quick checks include . . alternator belt tension battery electrolyte hydrometer reading of at least 1.230 battery cable clamps for corrosion and proper fit I connectors at alternator, regulator and starter relay for tight fit and clean connections fuse link integrity broken, damaged or shorted wires Alternator Warning Light Alternator warning light tails to come on with ignition switch at ON . . . I unplug regulator wiring connector I turn ignition switch to RUN (do not start) I jumper between regulator wiring connector l terminal to ground ltthewaminglightdoes notglovv . . . I check for burned out bulb . repair wiring to the light lithe ilght does glow . . . I replace the regulator. Alternator warning light stays on at allenglne speeds. .. I perform charging system tests. Charging System Tests To test torcurrent drain . t . I connect 12-volt test light In series with the POSITIVE cable terminal and the POSITIVE battery post I turn oil all switches and lights. It the light glows . . . I pull fuses one ata time until light goes out I check that circuit for possible shorts. To test for alternator/ regulator operation . . . I turn engine off I connect voltmeter to battery terminals I turn off all electrical accessories I record voltage as BASE VOLTAGE I turn ignition switch to ON "alternator warning light comes on . . . I start the engine. It the alternator warning light goes off. . . I run engine at 2000 rpm (approximately) I with accessories oft, record NO LOAD VOLTAGE. It N0 LOAD VOLTAGE is 1 to 2 volts above BASE VOLTAGE . . . I turn on headlights to high beam I turn heater blower to high I with engine at 2000 rpm, record LOAD VOLTAGE. If LOAD VOLTAGE is at least 0.5 volts higher than EASE VOLTAGE . . . I alternator and regulator are OK. It NO LOAD VOLTAGE isover 2 volts above BASE VOLTAGE . . . I stop engine I clean and tighten as necessary regulator mounting bracket and screws for good ground I Repeat NO LOAD VOLTAGE test NOTE: It NO LOAD VOLTAGE is too low. go to appropriate step ) If No LOAD VOLTAGE is too high . . V I unplug connector from regulator I repeat NO LOAD VOLTAGE test. It N0 LOAD VOLTAGE Is within specication . . . I replace regulator. Ii NO LOAD VOLTAGE is too high . . , I repair harness tor snons between regulator and alternator I reconnect regulator I repeat NO LOAD VOLTAGE test. M NO LOAD VOLTAGE is too high . t . I replace regulator. it No LOAD VOLTAGE is less than BASE VOLTAGE . , . I Disconnect regulator I Measure resistance between F terminal at regulator and ground. It resistance ls under 3 ohms . . . I repair grounded field circuit I replace regulator. It resistance ls over: ohms . . . I jumperterrninals A and F on regulator connector turn oft headlights and heater blower set engine at last idle measure battery voltage measure voltage at 5 terminal oi regulator connector. If the battery voltage is over 1 volt above base voltage . . . I check regulator wiring. it the battery voltage Is no higher than the base volmge . . . I turn off engine I iumperA and Fterminals ol regulator connector I measure voltage at alternator lield terminal I measure voltage at alternator output terminal. If both readings equal battery voltage . . . I replace alternator it both are not at battery voltage . . . I repair Wiring to terminals as necessary lithe S terminal voltage is zero . . . I repair ground between regulator connector and altemator If S termlnal voltage is between 1 and3orover9 . .. I repair or replace alternator Regulator Wiring Check To check regulator wiring . . . I unplug regulator connector I turn engine off I set ignition switch at RUN I measure voltage at l terminal at connector It voltage at l terrnlnal is not at battery voltage . . . I verify continuity lrorn S terminal of regulator connector through ignitiov switch to the alternator. If these checks are good . . . I replace the regulator, it these checks are not good . . i I repair the wiring.