Can someone tell me how to check the charging system/batteries? I'm getting slow starts but not sure if it is the alternator or batteries. A friend told me he got into a vicious cycle of replacing an alternator and then found out it had a bad battery and then something went wrong with the new alternator.

Is there a way to pinpoint the problem so I'm not purchasing something that is not necessary?

Jason

 

Jason,

I had a similar problem with my '02 back in '07. I replaced the alternator since I was on the road out of town. I could jumb start it, but it would not crank on its own.
With the new alternator from Advance I had to in thirty minutes and it cranked right up.
However, when I returned home I carried the relatively new batteries to Auto Zone and had them load tested - sure enough, one was bad, so I had both replaced under the three year full replacement warranty.
Almost exactly three years later - just the other day, I noticed it was starting to turn over slower and slower.
I checked the alternator charging by using a volt meter to see if both batteries were seeing 14.25 volts +/-. They were, so I yanked out the batteries and off to Auto Zone again. They load tested both and this time both were bad enough that they would not turn the engine over.
I had noticed one battery was using a lot of acid - liquid level was constantly getting low also.
I replaced the batteries and bam, it turned over like a new truck.
I never had a charging light on the dash to come on either and nothing else appeared abnormal.
Oh, if you replace the alternator and your batteries are not charged enough, you can possibly blow the new alternator.

Good luck,

 

^ Good advice. One tool that I find very useful is a Fluke, or any other quality digital multi meter. You can check output from the alternator, and voltage at the batteries. Also, check your battery connections. Mine were crusted and nasty so I had the terminals replaced with military terminals...