Battery Discharges

Fig. 9 Alternator Charging System:

Fig. 10 Terminal Locations:

When performing the following test, refer to Figs. 9 and 10.

1. Perform alternator quick test as follows:
a. Disconnect alternator R and L connectors.
b. Connect adapter harness 49U018003 or equivalent to alternator.
c. Connect checker lamp 49F018001 or equivalent to adapter harness.
d. Connect adapter harness red clip to battery positive terminal, then ensure red and green lamp illuminate. If lamps do not illuminate on 929, proceed to step 2 and, when results of step three are satisfactory, perform steps 5 and 6.
e. Start engine, then ensure both lamps go off. If lamps go off, proceed to step 2. If lamps do not go off, proceed to step 4 on B2200 & B2600, or steps 4d and 4e on 929.
2. Inspect IC regulator power source as follows:
a. Place ignition switch in Off position, then disconnect alternator terminal R connector.
b. Place ignition switch to On position, then measure R terminal voltage at connector. If battery voltage is present, proceed to step 3. If meter reads less than battery voltage, check for defective wiring harness.
3. Inspect output current as follows:
a. Start engine and allow to idle.
b. Turn on all lights and accessories and depress brake pedal.
c. Disconnect alternator B terminal electrical connector, then connect suitable ammeter between wire and terminal. Use caution not to ground B terminal.
d. Read meter at engine speed of 2500-3000 RPM. If meter reads 50 amps or less of idle output on B2200 & B2600 or 60 amps or less of idle output on 929, proceed to step 4. If meter reads 50 amps or more of idle output on B2200 and B2600 or 60 amps or more of idle output on 929, alternator is satisfactory.
4. Inspect output voltage as follows:
a. Turn all electrical loads off and release brake pedal.
b. Charge battery until charging rate indication becomes less than 5 amps or replace with new battery.
c. Read meter at engine speed of 2500 RPM. If meter reads less than 5 amps, proceed to step d. If meter reads more than 5 amps, proceed to step 5.
d. Connect alternator B terminal.
e. Measure L terminal voltage at an engine speed of 2500 RPM. If voltage is 14.2-15.2 volts at 68° F on B2200 and B2600 or 14.4-15 volts at 68° F on 929, proceed to step 5. If voltage is less than 14.2 volts or greater than 15.2 volts at 68° F on B2200 & B2600, or less than 14.4 volts or greater than 15 volts on 929, check for poor connection at battery terminals, B terminal and 2 prong connector or for defective stator coil or diodes.
5. Inspect rotor coil as follows:
a. Place ignition switch to Off position, then disconnect alternator B terminal and L and R connectors at alternator.
b. Measure resistance between alternator L and F terminals. If meter reads 3-6 ohms on B2200 & B2600, or 2-4 ohms on 929, proceed to step 6. If meter reads other than 3-6 ohms on B2200 and B2600, or other than 2-4 ohms on 929, rotor coil or slip ring is defective.
6. Inspect alternator L terminal voltage as follows:
a. Connect alternator B terminal and L and R connectors at alternator.
b. Place ignition switch to On position, then measure alternator L terminal voltage. If meter read 1-3 volts, alternator is satisfactory. If meter reads over 3 volts, IC regulator or rotor coil is defective.