Having a good checklist for troubleshooting the problems your alternator is having will save you time and money. Trying to figure out if you’ve got an alternator or a battery problem? Time after time we hear the stories of the battery mysteriously draining or the car stalls again after you’ve just checked all the wiring, connections, distributor cap and kicked the car a few times just for good measure. Here is a good checklist for troubleshooting problems with your alternator. It also includes how to check everything related like the battery, the connections and cables so you should be able to identify the possible culprit. (Warning: if you aren’t sure how to safely perform anything on this list please consult a professional)
Check the voltage on your alternator using a volt meter. If you don’t have one it’s possible that your local parts store may be able to help you or at least sell one to you and give you directions on using it. With all the accessories off the voltage should be 12.6 or higher prior to starting and at least 14.2 after starting. Note: voltage on some units may take a minute or so to stabilize.
Have your battery load tested, this can be done at your local auto supply store or your repair shop. If it doesn’t pass then it will need to be replaced.
Make sure you have the correct unit for the year, make, model and engine size. There are plenty of ways this can get mixed up; models that are known by more than one name and parts that can be used by more than one make so if it’s been replaced or if you bought the vehicle used have this checked.
Check the battery and load carrying cables to make sure they are clean and free of corrosion. If you have any crusty white material built up around the battery posts you will need to clean them to make sure you have a good connection. If they aren’t make sure you take some precautions: always remove the negative cable first, while removing the terminal don’t pull up because you could pull out the battery post and have an even bigger problem, try not to get the crud on your hands, eyes or anywhere on your body it’s corrosive and can be harmful.
Check for loose grounds and wire connections. This can be done by visually inspecting and gentling jiggling the wires.
Check alternator wiring connections for corrosion. Again work safely and if you are having a hard time identifying the negative cable to remove it first don’t guess get professional help.
Reset onboard computer, disconnecting the battery does not work for all systems for example on OBD II engine management systems, the disconnecting of the battery WILL NOT reset the computer. Except for the negative cable that connects to the car all of the other negative terminal cables connect to another battery. You will need to check your owner’s manual some vehicles have a reset button and sometimes your mechanic can use a scan tool.
Check belt, tensioner and idler pulley for wear and belt for correct tension. Your tensioner may be springloaded and not require adjusts because it adjusts itself. But belts shouldn’t be loose and if they are worn you will see fraying or cracking.
If you still aren’t sure give us a call we can help point you in the right direction, check to make sure you have the correct unit and order replacements parts. Give us a call at 800-457-1728.