Output Current Test

This test determines whether or not the alternator gives an output current that is equivalent to the normal output.

Preparation 

1. Prior to the test, check the following items and correct as necessary.

   Check the battery installed in the vehicle to ensure that it is good condition. The battery checking method is described in this service information "Battery".

   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.

   Check the tension of the alternator drive belt. The belt tension check method is described in this service information. Refer to "ON-VEHICLE INSPECTION - NON-TURBO ".

2. Turn off the ignition switch.
3. Disconnect the battery ground cable.
4. Disconnect the alternator output wire from the alternator "B" terminal.
5. 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.
   NOTE:

   Tighten each connection securely, as a heavy current will flow. Do not rely on clips.

6. 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.
7. Attach an engine tachometer and connect the battery ground cable.
8. Leave the engine hood open.
   Fig 1: Connecting Engine Tachometer To Battery Ground Cable

   Courtesy of HYUNDAI MOTOR AMERICA

Test 

1. 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 alternator "B" terminal and battery (+) terminal or poor grounding is suspected.
2. Start the engine and turn on the headlamps.
3. Set the headlamps 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 start up, 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 alternator output wire is in good condition, remove the alternator from the vehicle and test it.

   Limit value:  60% of the voltage rate

   NOTE:

   • The output current value changes with the electrical load and the temperature of the alternator itself. Due to temperature the maximum output current may not be obtained. If such is the case, keep the headlamps on to increase the electrical load. The 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.
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 alternator output wire to the alternator "B" terminal.
6. Connect the battery ground cable.