How to Troubleshoot a Taurus Alternator
- 1). Check the battery with the voltmeter by connecting the red lead to the positive terminal on the battery and the black, ground lead to the negative terminal on the battery. The voltage should indicate 12.5 volts for a full charge. If the battery is under 10.5 volts, it must be charged prior to troubleshooting the alternator. If after charging the battery, it does not reach the target voltage, replace the battery. If it does charge to 12.5 volts, proceed by having a helper start the vehicle. While the helper starts the vehicle, watch the voltmeter very closely. If the voltage drops below 10.5 volts as the starter is engaged, the battery has a bad cell and must be replaced.
- 2). Start the car and observe the voltmeter. The voltmeter should display 13.8 to 14.5 volts, indicating the alternator is charging sufficiently. If the voltage is lower, the alternator has a bad diode trio and needs to be replaced.
- 3). Turn on all the accessories such as headlights, alternator and air conditioning. Once again, check the voltmeter. The correct voltage should be 13.8 to 14.2 volts, indicating the regulator is operating and has increased the voltage output to handle the extra load. If the voltage drops significantly when the accessories are turned on, the alternator needs to be replaced.
- 4). Check the tightness on the serpentine belt. If the belt is not taut, the serpentine belt tensioner is at fault, causing the alternator belt to slip.
- 5). Listen for a whine or squeal in the alternator, which if present, would indicate a bearing failure in the alternator armature, requiring a replacement of the alternator.