Rick's Free Auto Repair Advice

Posts Tagged: alternator

Alternator overcharges battery Impala

How to fix an Alternator that overcharges battery Impala Shops are reporting instances where GM vehicles and specifically Chevrolet Impala alternators are overcharging the battery. The charging system in these newer GM vehicles is far more complicated than just a traditional voltage regulator and alternator. These systems incorporated and Electric Power Management (EPM) strategy to reduce the amount of time the alternator runs when charging isn’t needed. That saves gas. The system also monitors the state of battery charge when the engine is turned off. The body control module (BCM), … Read More

Nissan Alternator Problems

Fix Nissan Alternator Problems Shops report that Nissan Alternator Problems can sometimes be traced to an intermittent in the plug that goes into the voltage regulator in the alternator. The factory harness is short (less than 1 foot) and can fray the wires in the terminals. Nissan techs report that they replace this item quite frequently. Also, quality complaint abound on rebuilt alternators. Shop increasingly refuse to even install them due to the high failure rate. If you’re set on buying rebuilt, my advice is to buy Denso or Hitachi, … Read More

How to test an Alternator

How to test an alternator If you want to test an alternator all you need is a digital multimeter. But there are so old fashioned ways that many people still use on late model vehicles and those out of date methods can damage vehicle electronics. One of the most damaging ways to fry your vehicle electronics is to disconnect the battery cables while the engine is running. Cardone, a major re builder of alternators has issued a service bulletin regarding the right and wrong ways to test an alternator. How … Read More

Voltmeter fluctuates GM Trucks

The voltmeter fluctuates on my GM Truck GM has issued a technical service bulletin #07-06-03-009 regarding Voltmeter fluctuates GM Trucks. GM says fluctuating voltage on the vehicle’s voltmeter is NORMAL and is not a reason to replace any parts. The TSB applies to 2005-08 Cadillac Escalade, 2005-08 avlanche, Silverado, Silverado Classic, Suburban, Tahoe, 2005-08 GMC Sierra, Sierra Classic, and Yukon. The charging systems in these vehicles do not use an alternator decoupler to increase gas mileage. Instead they incorporate a Regulated Voltage Control (RVC) system. The RVC is controlled by … Read More

Battery Light On – Windstar

Battery Light On – Windstar Alternator rebuilders report a problem with ’98 Ford Windstars with battery light on. Do not automatically replace the alternator. First check for a corroded wire located below the brake vacuum booster. The wire can rub through against the heater hose. If you find a frayed or corroded wire, repair it first and then recheck the charging system.   © 2012 Rick Muscoplat

The safe way to test an alternator

How to test an alternator Disconnecting a battery cable while a car is running to test an alternator can damage your car’s computers and computerized controls. You could do that on non-computerized cars, but not on any car since the early ’80’s. What happens if you disconnect battery terminals while engine is running? When you start your car, the voltage regulator takes a look at battery voltage. If it’s at 12.7 volts, the regulator determines that the battery is in good shape and doesn’t need charging. But once you turn … Read More


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