56 SENR9977 Testing and Adjusting Section Electrical System 4. Turn the ignition switch to the ON position. Check the voltage between terminal (B) and ground. If the voltage is more than 2 Volts the alternator needs to be replaced. i01899123 Alternator - Test Warning Light is On When the Engine is Running 1. Start the engine and run the engine at fast idle. 2. Measure the voltage between terminal (A) and ground. 3. Measure the voltage between terminal (B) and ground. 4. The measured voltage for terminal (A) and terminal (B) should be 13 to 15 volts for a 12 volt system. The measured voltage for terminal (A) and terminal (B) should be 26 to 30 volts for a 24 volt system. 5.
If the voltages do not match replace the alternator. 6. Increase the engine to high idle. Turn an electrical load ON. 7. Measure the voltage between terminal (A) and ground. g00931045 Illustration 65 Typical wiring schematic for an alternator (A) Terminal (B) Terminal (C) Terminal (D) Ground (1) Electrical switch (2) Dash light (3) Ignition switch (4) Battery 8. Measure the voltage between terminal (B) and ground. 9. The measured voltage for terminal (A) and terminal (B) should be 13 to 15 volts for a 12 volt system. The measured voltage for terminal (A) and terminal (B) should be 26 to 30 volts for a 24 volt system. Warning Lamp Does Not Illuminate 10.
Replace the alternator if the voltage does not match. The warning lamp for the charging system should illuminate when the ignition switch is in the ON position. Follow the steps below in order to test the system. i01899136 Battery - Test 1. Check the light bulb. Replace the light bulb if the element is broken. 2. Use a suitable Multimeter to check the battery voltage. Check the battery voltage with the ignition switch OFF. Most of the tests of the electrical system can be done on the engine. The wiring insulation must be in good condition. The wire and cable connections must be clean, and both components must be tight. 3. Check the voltage between the terminal (A) and ground.
The measured voltage should equal the battery voltage.