Charging System Test

Fig. 6 Voltmeter test scale:

All lights and electrical systems in the off position, parking brake applied, transmission in neutral and a charged battery (at least 1.200 specific gravity).
1. Connect the negative lead of the voltmeter to the negative battery cable clamp (not bolt or nut).
2. Connect the positive lead of the voltmeter to the positive battery cable clamp (not bolt or nut).
3. Record the battery voltage reading shown on the voltmeter scale.
4. Connect the red lead of a tachometer to the distributor terminal of the coil and the black tachometer lead to a good ground.
5. Then, start and operate the engine at approximately 1500 RPM. With no other electrical load (foot off brake pedal and car doors closed), the voltmeter reading should increase but not exceed (2 volts) above the first recorded battery voltage reading. The reading should be taken when the voltmeter needles stops moving.
6. With the engine running, turn on the heater and/or air conditioner blower motor to high speed and headlights to high beam.
7. Increase the engine speed to 2000 RPM. The voltmeter should indicate a minimum reading of 0.5 volts above the battery voltage, Fig. 6. If the above tests indicate proper voltage readings, the charging system is operating normally. Proceed to ``Test Results'' if a problem still exists.

Fig. 7 Regulator plug jumper wire connection:

Fig. 8 Rear terminal alternator. Typical jumper wire connection:

Fig. 9 Side terminal alternator. Typical jumper wire connection.:

TEST RESULTS
Exc. Alternators W/Integral Regulators
1. If voltmeter reading indicates 2 volts over battery voltage (over voltage), proceed as follows:
a. Stop the engine and check the ground connections between the regulator and alternator and/or regulator to engine. Clean and tighten connections securely and repeat the Charging System Test Procedures.
b. If over voltage condition still exists, disconnect regulator wiring plug from regulator and repeat the Charging System Test Procedures.
c. If over voltage still exists with the regulator wiring plug disconnected, repair the short in the wiring harness between the alternator and regulator. Then, replace the regulator and connect the regulator wiring plug to the regulator and repeat the Charging System Test Procedures.
2. If voltmeter does not indicate more than {1-2} volt above battery voltage, proceed as follows:
a. Disconnect voltage regulator wire connector and connect an ohmmeter between wire connector ``F'' terminal and ground. If reading is less than 3 ohms on 1983---83 models, or 2.4 ohms on 1984---87 models, repair grounded field circuit and repeat Charging System Test procedure.
b. If ohmmeter reading is more than 3 ohms on 1982---83 models, or 2.4 ohms on 1984---87 models, connect a jumper wire between voltage regulator wire connector terminals A and F, Fig. 7, then repeat Charging System Test procedure. If voltmeter reading is now more than {1-2} volt above battery voltage, the voltage regulator or wiring is defective, refer to Regulator Test.
c. If voltmeter still indicates less than {1-2} volt, disconnect jumper wire from voltage regulator wire connector and leave connector disconnected from regulator. Connect a jumper wire between alternator FLD and BAT terminals, Figs. 8 and 9, then repeat Charging System Test procedures.
d. If voltmeter reading now indicates {1-2} volt or more above battery voltage, repair alternator to regulator wiring harness.
e. If voltmeter still indicates less than {1-2} volt above battery voltage, stop engine and move voltmeter positive lead to alternator BAT terminal.
f. If voltmeter now indicates battery voltage, the alternator should be removed, inspected and repaired. If zero volts is indicated, repair BAT terminal wiring.

Fig. 10 Charging circuit test points. Alternator w/integral regulator:

Alternators W/Integral Regulators
1. If voltmeter reading indicates 2 volts or over battery voltage (over voltage), proceed as follows:
a. Stop engine and place ignition switch in the ``On'' position, then connect voltmeter negative lead to the alternator rear housing.
b. Connect voltmeter positive lead first to the alternator output connection at the starter solenoid, then to the regulator ``A'' screw head, Fig. 10.
c. If the voltage difference between the two locations is greater than .5 volts, repair the ``A'' wiring circuit to eliminate the high resistance condition indicated by the excessive voltage drop.
d. If over voltage condition still exists, check for loose regulator to alternator grounding screws. Torque regulator grounding screws to 15---26 inch lbs.
e. If over voltage condition still exists, connect voltmeter negative lead to the alternator rear housing.
f. Place ignition switch in the ``Off'' position, then connect voltmeter positive lead first to the regulator ``A'' screw head and then to the regulator ``F'' screw head, Fig. 10.
g. Different voltage readings at the two screw heads in step 1f indicates a defective regulator, grounded brush lead or grounded rotor coil. Repair or replace as required.
h. If battery voltage is obtained at both screw heads in step 1f, replace regulator.
2. If voltmeter does not indicate more than .5 volts over battery voltage, proceed as follows:
a. Disconnect wiring plug from regulator, then connect an ohmmeter between regulator ``A'' and ``F'' terminal screws, Fig. 10. Meter should indicate more than 2.4 ohms.
b. If meter indicates less than 2.4 ohms in step 2a, check integral alternator/regulator unit for a defective regulator, then check the alternator for a shorted rotor or field circuit. Perform Charging System Test procedure after servicing alternator. Do not replace the regulator until a shorted rotor coil or field circuit has been serviced.
c. If meter indicates greater than 2.4 ohms in step 2a, reconnect regulator wiring plug. Connect voltmeter ground lead to the alternator rear housing and voltmeter positive lead to the regulator ``A'' terminal screw.
d. Meter should read battery voltage. If battery voltage is not present, repair ``A'' wiring circuit, then perform Charging Circuit Test procedure. If battery voltage is present, connect the voltmeter ground lead to the alternator rear housing.
e. Place ignition switch in the ``Off'' position, then connect voltmeter positive lead to the regulator ``F'' terminal screw. Meter should indicate battery voltage.
f. If voltage is not present, check integral alternator/regulator unit for an open field circuit. Repair as required, then perform Charging Circuit Test procedure. If voltmeter indicates battery voltage, connect voltmeter negative ground lead to alternator rear housing.
g. Turn ignition switch to the ``On'' position and connect voltmeter positive probe lead to the regulator ``F'' terminal screw. Voltmeter should indicate 1.5 volts or less.
h. If more than 1.5 volts is present, proceed to ``I Circuit Test.'' If ``I Circuit'' is satisfactory, replace the regulator and preform Charging Circuit Test procedure. If 1.5 volts or less is present, disconnect alternator wiring plug and connect suitable jumper wires between the alternator B(+) terminal and mating wiring connector terminals.
i. Perform Charging System Test procedure, but connect voltmeter positive terminal to one of the B(+) jumper wire terminals.
j. If voltage rises more than .5 volts above battery voltage, check alternator and starter relay wiring, then repeat Charging System Test procedure, measuring voltage at battery cable clamps.
k. If voltage does not rise more than .5 volts above battery voltage, connect jumper wire from alternator rear housing to the regulator ``F'' terminal.
l. Repeat Charging System Tests procedure with voltmeter positive lead connected to one of the jumper wire terminals.
m. If voltage rises more than .5 volts, replace regulator. If voltage does not rise more than .5 volts, service the alternator.