Removal & Installation
Visually check the alternator wiring and listen for abnormal noises. Check that the wiring is in good condition. Check that there is no abnormal noise from the alternator while the engine is running.Output Current Test
This test determines whether or not the alternator gives an output current that is considered normal. Prior to the test, check the following items and correct as necessary. Check the battery installed in the vehicle to ensure that it is in good condition. The battery checking method is described in the "BATTERY" section. 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. Check the tension of the alternator drive belt.
- Turn off the ignition switch.
- Disconnect the battery ground cable.
- Disconnect the alternator output wire from the alternator "B" terminal.
Connect a DC ammeter (0 to 150A) 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.
NOTETighten each connection securely, as a heavy current will flow. Do not rely on clips.
- Connect a voltmeter (0 to 20V) between the "B" terminal and ground.
- Connect the (+) lead wire to the alternator "B" terminal and (-) lead wire to a good ground.
- Attach an engine tachometer and connect the battery ground cable.
Leave the engine hood open.
Check to see that the voltmeter reads as the same value as the battery voltage. If the voltmeter reads 0V, and the open circuit in the wire between the alternator "B" terminal and battery (-) terminal, a blown fusible link or poor grounding is suspected.
- Start the engine and turn on the headlights.
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.
NOTEAfter the engine starts up, the charging current quickly drops. Therefore, the above operation must be done quickly to read the maximum current value correctly.
The ammeter reading must be higher than the limit value. If it is lower but the alternator output wire is in good condition, remove the alternator from the vehicle and test it.
Limit value (90A alternator) = 63A min.
NOTEThe nominal output current value is shown on the nameplate affixed to the alternator body. The output current value changes with the electrical load and the temperature of the alternator itself. Therefore, the nominal output current may not be obtained. If such is the case, keep the headlights on to cause discharge of the battery, or use the lights of another vehicle to increase the electrical load.
NOTEThe nominal output current may not be obtained if the temperature of the alternator itself or ambient temperature is too high. In such a case, reduce the temperature before testing again.
- Upon completion of the output current test, lower the engine speed to idle and turn off the ignition switch.
- Disconnect the battery ground cable.
- Remove the ammeter and voltmeter and the engine tachometer.
- Connect the alternator output wire to the alternator "B" terminal.
- Connect the battery ground cable.
This test determines whether or not the wiring between the alternator "B" terminal and the battery (+) terminal is good by utilizing the voltage drop method.
- Before servicing the vehicle, refer to the Precautions Section.
Turn the ignition switch to "OFF".
NOTETo find abnormal conditions of the connection, actions should not be taken on the two terminals and each connection during the test.
Connect a digital voltmeter between the alternator "B" terminal and battery (+) lead wire to the battery (+) terminal.
- Start the engine.
- Switch on the headlamps, blower motor and so on. And then, read the voltmeter under this condition.
- The voltmeter may indicate the standard value.
- Standard value = 0.2V max.
If the value of the voltmeter is higher than expected (above 0.2V max.), poor wiring is suspected. In this case check the wiring from the alternator "B" terminal to the fusible link to the battery (+) terminal. Check for loose connections, color change due to an overheated harness, etc. Correct them before testing again.
- Upon completion of the test, set the engine speed at idle. Turn off the head lamps, blower motor and the ignition switch.