Why does my alternator light go off when I raise the RPM?
Then if this light is going off when you raise the RPM then that means by spinning the alternator faster to increase the output puts the voltage over the minimum spec to turn the light off. If all this checks out then I suspect you have a wiring issue.
What happens when an alternator fails in a car?
When an alternator fails not only will the battery light come on but it can cause the check engine or service engine soon warning lights to come on. Never disconnect the battery while the engine is running to check the charging system.
Why does my alternator show a check engine light?
Additionally when an old battery is replaced the alternator will show a high state of charge because a new battery requires less effort to maintain than the aged battery, this may cause a check engine light. This will require a charging system reset using a code scanner capable of this task.
What should my alternator voltage be at idle?
Have a helper start the engine and hold the RPM’s just above idle at about 1500 and observe the meter. It should read between 13.6 and 15.2 volts depending on battery condition and state of charge. If the voltage on the meter stays the same or drops when the engine is started the alternator is not charging.
Why does the battery warning light come on after replacing the alternator?
A relatively common “side-effect” of replacing a battery and/or alternator in a car is to have the voltage (battery) warning light come on. This is especially true in late-model vehicles with their more sophisticated internal diagnostic systems.
What causes an alternator to go over base voltage?
If you are getting more than 2 volts above base voltage, most likely your alternator is over-charging the battery or the battery is faulty. Other potential problems are a faulty voltage regulator or a problem in the charging system wiring.
How to know if your alternator is working properly?
1 Check the drive belt or serpentine belt. Look for signs of wear or damage like cuts, shiny spots or missing chunks under the belt. 2 Also, check the belt tensioner for proper operation and damage. It should rotate freely. 3 Make sure the alternator is properly mounted. 4 Check the alternator for noises.
What happens when the diodes in an alternator go bad?
Alternators use diodes to rectify alternating current produced by the alternator into direct current. When one or more diodes go bad, the alternator can cause all kinds of problems. AC voltage leak can cause your lights to dim and drain power from your battery, for example.