My truck wouldnt start last night so I had to get a jump. After I got a jump and got the engine running, I noticed that the lights on the dash board were flickering on and off. Is this a battery problem or an alternator problem?

 

If it wont start then you already know you have a battery issue. I would start from there. Take it to AutoZone or Advance or PBs and get them to check it all out.

 

agree...

 

liights should have been fine once you got running (alternator should have kept it up). might be the alternator too. is the battery light on the dash lit?

 

Bad alternator can still drain a perfectly good battery.
However, if you did bring it in for a check/charge then they will tell you or not if it's holding a charge.
If the battery is deemed good, then i would pick up an alternator while your there.

 

And a bad battery will wear out a good alternator. Yeppir, get 'em both checked. That'll be an expensive combo if you have to get both. Anyway, the alternator should be "cave man easy" to change.

 

After jump starting the lights may flicker the alt is on or off thats all a low battery will let you see this happen cummins drivers notice this on cold starts when it takes a lot to start. the alt and pcm maintain battery voltage but there is no regulator The pcm takes care of it have the charging sys checked after you have a good charge or a new battery