When does a GM alternator need to be replaced?

When does a GM alternator need to be replaced?

A GM alternator that is producing too much voltage must be replaced. When a car does not start or the lights are dim, it may be because the voltage output has dropped lower than 13.5 volts. When this happens, the battery is not being charged, and the electrical systems of the vehicle will fail.

How can I tell if I have an alternator problem?

To differentiate an alternator problem from the battery, you will need to use a voltmeter to check for voltage. First, turn off the engine and check the battery voltage. A fully charged battery should have a reading of 12.65 volts. Next, turn on the engine and recheck the voltage. You should have a reading of 13.5 to 14.5 volts.

Can a bad alternator cause a car to not start?

A bad alternator can killing your car’s battery, even if the battery wasn’t the problem to begin with. Natnan Srisuwan/ThinkStock While not technically an alternator problem, a car that won’t start is a definitive sign that there’s a problem in the starting system.

Can a stuck regulator cause an alternator to overcharge?

The external regulator usually has three electromagnetic contact switches inside its housing that open and close. A stuck contact switch that refuses to disengage will cause an overcharging problem. The internal regulator, or “internally regulated” regulator, has been used as a replacement for older, externally mounted regulators.

To differentiate an alternator problem from the battery, you will need to use a voltmeter to check for voltage. First, turn off the engine and check the battery voltage. A fully charged battery should have a reading of 12.65 volts. Next, turn on the engine and recheck the voltage. You should have a reading of 13.5 to 14.5 volts.

Why does my alternator not work when I jump start my car?

Improperly jump starting a car As with the car battery, switching jump cables can cause alternator problems. Namely, if you switch the plus and minus cables (from the “donor” car to yours) you can again damage the diode rectifier. Even worse, you can damage the “donor” car as well.

What does it mean when your alternator is not charging?

If the alternator is not charging the battery, you will have a red “ALT” or “charge” sign on your dashboard. This means that your battery is no longer being supplemented for power by the alternator. You will need to recheck the wiring because the light could also be faulty.

What should the voltage be on a car alternator?

12.6v is the optimal battery voltage. 13 -14v is the average alternator output. Depending on the load on the electrical system, anything higher than battery voltage is good voltage for a vehicle. Current is a different story.