Component Tests and General Diagnostics
INSPECT CHARGING SYSTEMVOLTAGE DROP TEST
This test determines if the wiring between the generator "B" terminal and the battery (+) terminal is good by the voltage drop method.
PREPARATION
1. Turn the ignition switch to "OFF."
NOTE: To identify connection problems, be sure not to disturb either of the two terminals or their connections during this test.
2. Connect a digital voltmeter between the generator "B" terminal and battery (+) terminal. Connect the (+) lead wire of the voltmeter to the "B" terminal and the (-) lead wire to the battery (+) terminal.
CONDITIONS FOR TESTING
With the engine running and headlamps, blower motor etc. ON, check the reading on the voltmeter.
RESULT
1. The voltmeter should read a standard 0.2 V.
2. If the reading is above 0.2 V, poor wiring should be suspected.
Check wiring from generator 'B' terminal through the fusible link to the battery (+) terminal.
Check for loose wiring or color change from an over-heated harness. Correct and check again.
3. On completion of the test, set the engine at idle.
Then turn off the headlamps, blower motor etc., and ignition.
OUTPUT CURRENT TEST
This test determines if the generator gives an output current that is equivalent to the nominal output.
PREPARATION
1. Prior to the test, check the following items and correct as necessary.
1. Check if that the battery installed in the vehicle is in good condition. For details, see "BATTERY".
NOTE: The battery that is used to test the output current should be one that has been partially discharged. With a fully charged battery, the test may not be conducted correctly due to an insufficient load.
2. Check the tension of the generator drive belt. See "COOLING".
2. Turn the ignition switch to "OFF"
3. Disconnect the battery ground cable.
4. Disconnect the generator output wire from the generator "B" terminal.
5. Connect a DC ammeter (0 to 100 A) in series between the "B" terminal and the disconnected output wire. Be sure to connect the (-) lead wire of the ammeter to the disconnected output wire.
NOTE: Tighten each connection securely, as a heavy current will now. Do not rely on dips.
6. Connect a voltmeter (0 to 20 V) between the "B" terminal and ground. Connect the (+) lead wire to the generator "B" terminal and (-) lead wire to a good ground.
7. Attach an engine tachometer and connect the battery ground cable.
8. Leave the engine hood open.
TEST
1. Check to see that the voltmeter reads the same value as the battery voltage. If the voltmeter reads 0 V, an open circuit in the wire between the generator "B" terminal and battery (-) terminal, a blown fusible link or poor ground is suspected.
2. Start the engine and turn the headlights on.
3. Set the headlights to high beam and the heater blower switch to HIGH, quickly increase the engine speed to 2,500 rpm and read the maximum output current value indicated by the ammeter.
NOTE: After the engine starts, the charging current quickly drops. Therefore, the above operation must be done quickly to read the maximum current value correctly.
RESULT
1. The ammeter reading must be higher than the limit value. If it is lower but the generator output wire is in good condition, remove the generator from the vehicle and test it.
Limit value : 45 A
NOTE:
1. The nominal output current value is shown on the nameplate affixed to the generator body.
2. The output current value changes with the electrical load and the temperature of the generator itself. Therefore, the nominal output current may not be obtained. In such case, keep the headlights on to discharge the battery, or use the lights of another vehicle to increase the electrical load.
The nominal output current may not be obtained if the temperature of the generator itself or ambient temperature is too high.
In such a case, reduce the temperature before testing again.
2. Upon completion of the output current test, lower the engine speed to idle and turn off the ignition switch.
3. Disconnect the battery ground cable.
4. Remove the ammeter and voltmeter and the engine tachometer.
5. Connect the generator output wire to the generator "B" terminal.
6. Connect the battery ground cable.
REGULATED VOLTAGE TEST
The purpose of this test is to check that the electronic voltage regulator controls the voltage correctly.
PREPARATION
1. Prior to the test, check the following items and correct if necessary.
1. Check that the battery installed in the vehicle is fully charged. For battery checking method, see "BATTERY".
2. Check the generator drive belt tension. For belt tension check, see "COOLING."
2. Turn ignition switch to "OFF."
3. Disconnect the battery ground cable.
4. Connect a digital voltmeter between the "S(L)" terminal of the generator and ground.
Connect the (+) lead of the voltmeter to the "S(L)" terminal of the generator. Connect the (-) lead to a good ground or the battery (-) terminal.
5. Disconnect the generator output wire from the generator "B" terminal.
6. Connect a DC ammeter (0 to 100A) in series between the "B" terminal and the disconnected output wire. Connect the (-) lead wire of the ammeter to the disconnected output wire.
7. Attach the engine tachometer and connect the battery ground cable.
TEST
1. Turn on the ignition switch and check to see that the voltmeter indicates the following value.
Voltage : Battery voltage
If it reads 0 V, there is an open circuit in the wire between the generator "S(L)" terminal and the battery and the battery (+), or the fusible link is blown.
2. Start the engine. Keep all lights and accessories off.
3. Run the engine at a speed of about 2,500 rpm and read the voltmeter when the generator output current drops to 10 A or less.
RESULT
1. If the voltmeter reading agrees with the value, the volt- age regulator is functioning correctly. If the reading is other than the standard value, the voltage regulator or the generator is faulty.
2. Upon completion of the test, reduce the engine speed to idle, and turn off the ignition switch.
3. Disconnect the battery ground cable.
4. Remove the voltmeter, ammeter, and the engine tachometer.
5. Connect the generator output wire to the generator "B" terminal.
6. Reconnect the battery ground cable.