Alternator/Regulator Output Test
- Test system using an alternator tester with integral carbon pile (to apply electrical load to system). Hook up tester according to manufacturers instructions. Turn tester selector to STARTING position. Start engine and bring to operating temperature. Raise engine speed to 2000 RPM and hold. Observe voltmeter. If voltage is greater than 15.2 volts, replace voltage regulator.
- If voltage is less than 15.1 volts, return engine to idle. Ensure all accessories are off. Turn tester selector to CHARGING position. Remove inductive pick-up and zero ammeter. Connect inductive pick-up over alternator battery terminal (ensure arrow points away from alternator). See Fig 1.
- Raise engine speed to 2000 RPM and hold. Observe voltmeter. If voltage is greater than 13.9 volts, go to next step. If voltage is less than 13.9 volts, test battery condition. Recharge or replace battery as necessary.
- While observing ammeter, apply load with alternator tester carbon pile until battery voltage drops to 12-13.5 volts. If less than 40 amps are present, go to next step. If more than 40 amps are present, charging system is functioning properly.CAUTION: Voltage will rise rapidly during full field test. DO NOT allow voltage to exceed 18 volts. Damage to electrical system may result.
- With engine speed still at 2000 RPM, full field alternator. Attach probe to alternator tester full field test lead. Insert probe into full field access hole located on back of alternator. See Fig 1. Switch field selector to "A" (ground) position briefly and observe amperage reading. If more than 40 amps are present, go to next step. If less than 40 amps are present, test and repair alternator components. See BENCH TESTING .
- Return engine to idle and turn ignition off. Disconnect alternator 4-pin harness connector. Turn ignition on. Measure voltage between ground and alternator 4-pin harness connector terminal "IG" (Black/Yellow wire). See Figure. If battery voltage is present, replace voltage regulator. If battery voltage is not present, repair open in Black/Yellow wire.