SUPPORT AS 3544757 - Caterpillar

Probable Causes
Alternator
Condition of the alternator drive belts
Electrical operation of the alternator
Condition of the alternator bearings
Condition of the alternator drive pulleyCharging Circuit
Inspection of the charging circuit
Condition of the batteriesRecommended Actions
Note: The procedures have been listed in order of probability. Complete the following procedures in the order that is provided.Condition of the Alternator Drive Belts
Inspect the condition of the alternator drive belts. If the alternator drive belts are worn or damaged, replace the belts. Refer to Disassembly and Assembly for the correct procedure.
Check the belt tension. If the engine is equipped with an automatic belt tensioner, check the automatic belt tensioner. If necessary, replace the automatic belt tensioner. Refer to Disassembly and Assembly for the correct procedure. Note: Excessive belt tension may result in damage to the alternator.Electrical Operation of the Alternator
Verify the electrical operation of the alternator.
Use a battery tester to verify that the batteries are fully charged. If the condition of the batteries is suspect, perform a load test in order to ensure that the batteries are ok. If necessary, replace the batteries.
Install a 225-8266 Ammeter Tool Gp to the engine's battery cable.
Measure the current draw while the engine is not running.
While the engine is not running, apply a load to the electrical system. If equipped, use engine accessories such as headlights or a blower motor to load the electrical system.
Record the meter reading. Record the orientation of the meter installation. Note: Ensure that you record the orientation of the meter installation. Be sure to record a positive current draw or a negative current draw for the electrical system.
Remove the load from the electrical system.
Confirm that the alternator is applying current to the engine's electrical system.
Start the engine.
Apply a strong load to the electrical system. If equipped, use loads such as headlights, auxiliary lighting, and the heater's blower motor.
Again, record the meter reading. Record the orientation of the meter installation. Note: Ensure that you record the orientation of the meter installation. Be sure to record a positive current draw or a negative current draw for the electrical system.
Remove the load from the electrical system and shut down the engine.
Compare the current readings that are recorded. Determine if the current flow had changed from a state of discharge to a state of charge. If the ammeter readings indicate that the electrical system changed from a state of discharge to a state of charge, the alternator is operating correctly.If the ammeter readings indicate that the system remained in a state of discharge during the test, the alternator may need to be replaced.For additional testing procedures, refer to Special Instruction, REHS0354, "Charging System Troubleshooting". Repair the alternator or replace the alternator, as needed.Condition of the Alternator Bearings
Check the alternator bearings for signs of wear. Repair the alternator or replace the alternator, as needed. Refer to Disassembly and Assembly for the correct procedure.Condition of the Alternator Drive Pulley
Check the condition of the alternator drive pulley. If there is excessive wear, replace the pulley. Check that the nut for the