Battery or alternator?

[jrs6494]

Here is my problem. This morning my truck would not start just clicked. Had to get a ride to work.

When I came home I tried to diagnose the issue. When I turned the key to on I saw that my battery level was just below the black line. I decided to jump the truck with my wife's car.

I left the vehicles attached for about a minute or two. The truck started right up. We then disconnected the cables. The tuck continued to run.

I then sat in the truck for about 30 minutes and let it run. I read online about different ways to test the alternator vs battery. I turned the air on high, radio on, lights on inside, headlights on high beam and had little to no change with the battery gauge. I then pushed 3 of the 4 windows up to drain more power. This time the battery gauge began to drop but kinda slowed or stopped near a quarter on the gauge.

A couple of hours later I started the truck right up and the battery showed just over half on the gauge.

So is this a battery issue or alternator issue? I am leaning towards battery because the truck ran for 30 minutes with various items on and never stopped.

The battery is only a year to a year and a half old but not sure if that makes a difference if it's just a bad battery.

Please let me know your thoughts.

 

[RonJon '06]

Probably the battery. Easiest way to tell is to bring it in and get it tested. If it tests OK then might want to have alternator tested next.

 

[dmacell1]

If you have a volt meter it should read 14+ volts across the terminals when the vehicle is running. If not the alternator is prolly going.
Most places will test the battery for free.

 

[AK_Armendariz]

It's most likely the battery. (I'm pretty sure that this works for Rams and cars) but turn the key to on and then back to off a couple times and it should give you a code to tell you if its the battery or the alternator.