Heavy Duty Alternator Charging System Troubleshooting

Transcription

1 Heavy Duty Alternator Charging System Troubleshooting

2 Alternator Charging System Troubleshooting Squealing noises under the hood? Headlight bulbs blow out repeatedly or dim? Is the dash voltmeter gauge out of range - either too high or too low? These are common indicators that something may be wrong with the charging system. If any of these symptoms are evident, then follow these five steps to pinpoint the issue. Helpful Hint: If you find something wrong at any step, it s wise to complete the remaining steps anyway to ensure you ve given the charging system a thorough review Perform Visual Inspection Inspect Battery Battery Voltage Test Battery Load Test Measure Voltage at Battery Test Alternator Output Troubleshoot per Service Manual Visit to watch our Tech Tip videos Troubleshooting Complete Technical Assistance

3 1 Perform Visual Inspection Perform a visual inspection under the hood Look at the belt tension and condition. Next, check electrical connections and cables for corrosion and proper tightness. Finally, make sure the alternator is mounted properly. Belt Tension and Condition OK? No Perform Repairs Yes Electrical Connections OK? No Perform Repairs Yes Alternator Mounted OK? No Perform Repairs Yes Visual Inspections Complete Visit to watch the Alternator Charging System Tech Tip video

4 2.A Inspect Batteries Visually inspect and test the batteries Inspect the batteries for any signs of physical damage, cracks in the casing, loose terminals or leaking fluid. Clean, repair connection and replace any damaged batteries found. Ensure that all batteries used in the same circuit are of the same manufacturer, CCA rating type and age. Then test the batteries using a standard battery test. Remember that realistic testing, as well as successful operation, requires a fully charged battery, capable of supplying the starting system s current needs. Corrosion or Loose Connections? Yes Perform Repairs No Battery Damaged? Yes Replace Battery No Perform Battery Voltage Test Visual Inspection Complete Technical Assistance

5 2.B Battery Voltage Test Test the batteries using a standard battery test. Remember that realistic testing, as well as successful operation, requires a fully charged battery, capable of supplying the starting system s current needs. DC AMP 12.4 DC VOLTS Connect Voltmeter to Battery With Engine Off, Remove Surface Charge and Wait Two Minutes Visit to watch the Alternator Charging System Tech Tip video Measure Voltage < 12.4 Volts Recharge Battery 12.4 Volts Perform Battery Load Test Battery Voltage Test Complete Visit to watch the Alternator Charging System Tech Tip video

6 2.C Battery Load Test Connect Carbon Pile and Voltmeter to Battery 12.5 Adjust Carbon Pile to One-half the Cold Cranking Amp Rating for 15 Seconds Visit to watch the Alternator Charging System Tech Tip video Record Lowest Voltage < Minimum Loaded Voltage Replace Battery Minimum Loaded Voltage Battery Passes Battery Load Test Complete Technical Assistance

7 3.A Measure Voltage at Battery Fig 1. With the engine running, use a voltmeter to measure voltage at the battery. If voltage is greater than or equal to 13.8 volts, you can move on to Step 4. DC AMP 12.4 DC VOLTS Fig 1 Visit to watch the Alternator Charging System Tech Tip video Fig 2. However, if it is less than 13.8 volts, then you should measure voltage at Alternator B+ and the alternator case. (Note: If the model is insulated, you have to use a ground stud to get a reading.) DC AMP 13.0 DC VOLTS At that point, if the voltage falls between 12.6 and 13.7 volts, you need to replace your alternator. If it s greater than or equal to 13.8 volts, a voltage drop test needs to be performed. Learn how to perform a voltage drop test by visiting our YouTube page and watching our Tech Tip - Voltage Drop Test video. Link: tinyurl.com/delcoremyvideos. Fig 2 Visit to watch the Alternator Charging System Tech Tip video Visit to watch the Alternator Charging System Tech Tip video

8 3.B Measure Voltage at Battery Connect Voltmeter to Battery Turn Engine On Measure Battery Voltage < 13.8 Volts Connect Voltmeter to Alternator B+ and Ground Post 13.8 Volts Measure Voltage 12.6 to 13.7 Volts Replace Alternator 13.8 Volts Perform Voltage Drop Test Voltage at Battery Measured Technical Assistance

9 4 Test Alternator Output You can use either an automated tester or a manual process to determine the output of the alternator. If the alternator doesn t pass this test, then it needs to be replaced. Connect Carbon Pile, Ammeter and Amp Clamp Engine Running at Governor Speed and Electrical Loads Off Load Carbon Pile until Ammeter Reads Highest Value Visit to watch the Alternator Charging System Tech Tip video Record Output < 90% of Rated Capacity Replace Alternator 90% of Rated Capacity Alternator Output Test Complete Visit to watch the Alternator Charging System Tech Tip video

10 5 Troubleshoot Using the Service Manual If you ve passed through the first four steps, then the alternator is working as designed and your problem is likely caused by something external to the alternator. 1 2 Perform Visual Inspection Inspect Battery Battery Voltage Test Battery Load Test Measure Voltage at Battery Test Alternator Output Troubleshoot per Service Manual Troubleshooting Complete Remy International, Inc. 600 Corporation Drive Pendleton, IN USA For Technical Assistance call delcoremy.com Delco Remy is a registered trademark of General Motors Corporation, icensed to Remy Inc., Pendleton, IN Remy International, Inc. Technical Assistance