Charging System Diagnosis
The following general information has been assembled as a guide for charging system diagnosis. Refer to the appropriate Original Equipment Manufacturer’s service manual for specific information pertaining to charging system diagnostic procedures and safety precautions for your vehicle.
Bench Testing: RECONIT ELECTRIC provides alternator test bench facility. Contact : 519-748-6488. This test will determine if the alternator output is within its performance specification, preventing unnecessary alternator replacement.
If the alternator output is within specification during bench testing, resolve problems in the remainder of the vehicle’s charging circuit and other electrical circuits that may affect charging circuit performance. Refer to the vehicle manufacturer’s service manual for the procedures necessary to identify and correct additional charging circuit problems.
If the test bench results show the alternator output to be out of specification, replace the alternator. Follow the vehicle manufacturer’s recommended procedures to inspect the remainder of the charging circuit and other electrical circuits that may affect charging circuit performance.
Whether or not a test bench was used to determine the condition of the alternator, the following Helpful Tips have been assembled to help isolate conditions that may affect charging circuit performance.
1. What is the condition of the battery?
- A visual inspection and a performance test of the battery must always be performed before inspecting the charging system. The battery must be fully charged (12.6 volts) and the battery cables, terminals and case in good clean condition. (refer to Battery Visual Inspection and Performance Testing).
2. Does a charge lamp, amperage (amp) gauge or voltmeter indicate a charging system problem?
- Ignition ON engine not running: The charge lamp should illuminate.
- Ignition ON engine running: The charge lamp should illuminate briefly then turn OFF.
- Weak Battery: A weak battery can cause the charge lamp to illuminate during high amperage draw.
- Low Idle : A low idle can cause the charge lamp to illuminate dimly.