Battery light help needed

[DailyDriver03]

So for the past week or so after driving for a few minutes my battery light comes on. Nothing else. So I checked my battery posts and terminals and saw they were corroded. I cleaned them and it worked for a day or two. I had the battery tested and it was fine. It also said the alternator was fine. Well today the battery light came on, and my lights went dim and the car wasnt shifting into the next gear(automatic). I pulled over and turned car off. Then it wouldn't start. It jumped and ran good. So I bought a battery cleaner and protectant kit. I applied and then later on had the issues all over again. What is my problem ???!!!! Please someone help!!!! Can it be the alternator.....I hope that's all it is and not a bigger electrical issue!!!!

 

[Cardhu]

the kj acts funny when you have a battery that is low or on its way out. Put it on a trickle charger and see if things improve. I used to do it to mine about once a month in the winter.

most garages can make sure its not your alternator but i'm sure somebody has a more elaborate way of testing it past putting leads on your terminals while the jeep is running and comparing it to the voltage before starting.

 

[rockymountain]

How old is the battery should be what you ask yourself first.

And what Cardhu said.

 

[Billwill]

As stated...how old is your battery?
You need to make sure the terminals are clean and tight and check the earthing strap that goes from the engine to the chassis is clean and tight.
Put a voltmeter across the battery...while the engine is running you should get about 13.5 volts reading if your alternator is charging.
About 99% of these problems are fixed by replacing the battery.

 

[DailyDriver03]

I said screw it and replaced the alternator since I knew the battery was fine....it worked. Glad it wasn't more serious.

 

[Ry' N Jen]

I would of tried a new battery first.