I bought my 02 2500 hd a few months ago. It has a 6.0 gas. It had dual batteries. Every time i tried to start it , it would just click. I disconnected the passenger side battery & now it starts everytime. Can anyone tell me why? Is the second battery not needed?

 

You know what they say about if it ain't broke don't fix it. Seriously have you checked the second battery out? Could be causing a parasitic drain.

 

Have the second battery tested at a battery shop. It could be pooched.