My battery and brake light stay on when my car is running but only sometimes. Sometimes they don't turn on at all and wont turn on the whole drive. Anyone know what's going on here?

 

Seems like the alternator is going. Check the connector and test the battery while the car is off and on. 12.4 and 14.2.....check also the battery terminals

 

Funny thing is that the battery and alt are brand new. Less than 20 miles.

 

It seems wrong, but don't assume brand new parts will function properly. But maybe it's the ground connection or battery connections are loose.

Like suggested, check connections.

 

you didn't specify that in your post. Check the connectors and grounds

 

 

If your brake lights are staying on then your problem isn't the alternator at all! It's your brake switch detent rubber bumper is gone bye-bye! That'll eat your battery in a few hours, and show no lights once your battery is depleted! Look under your dash and there should be a bumper to press against the brake switch if not that's your real problem!!!! Get yourself a small machined screw, 2 washers, and 2 nuts! Have fun!

 

From my personal experience the brake light and battery light mean the alternator is bad or going bad. I had a 2003 SE and I subsequently had 2 brand new AutoZone alternators installed that both failed within a few days of them being installed. It took me demanding that the shop spend the extra money and get an OEM alternator from the dealer before my problem was fixed.

 

My bad I thought he was referring to the exterior brake lights not the instrument panel brake warning light....

 

Replaced the Alternator. It was definitely faulty.

 

If you are able, get it to an electrical rebuider and even though it is "new" have them go over it. It will be better and last longer than the parts store ones.

 

I have a lifetime warranty. They just replace it for free until I sell the car.

 

ok. I can see why you don't want to spend more on it.

However, keep it in mind next time. This alt is not.a quick job. No fun if you have to do it often.