Alternator issues?

MANTII

MEMBER
2009 TOYOTA COROLLA
40,000 MILES

While driving battery light came on car slowed down and my son pulled on aide of road. Battery tested fine. Seems like an alternator issue which may be covered on extended warranty. Curious if ya'll know if keyless entry is connected to alternator because Toyota dealer shop installed keyless twelve days prior. Just curious because if its not a warranty issue it will cost tons of money to tow when if its a loose belt I can maybe ask a local mechanic to check it out. I totally understand there is no way of knowing unless its checked out but just curious if installing the keyless entry (not remote start just entry) could have done something. Thank ya'll in advance!

1 Reply

KASEKENNY

MECHANIC
18,907 POSTS

Short answer is yes it could be related but if the battery tested okay, then it is unlikely to be an alternator as the alternator normally fails and then the light comes on when the battery drains. However, we need to test it.

Here is a guide that will help with this:

https://www.2carpros.com/articles/how-to-check-a-car-alternator

If the alternator fails then it needs to be replaced. Here is a guide for that as well:

https://www.2carpros.com/articles/how-to-replace-an-alternator

If the alternator does not fail the test I suspect we have an issue with the voltage regulator which regulates the amount of voltage needed.

Let's start with this and go from there. Thanks