If you have a big sound system in your truck then it could be a good idea to add a second battery, also if you have a winch or some kind of after market lights then you might want to add another battery so you don't stress the single battery.
under the battery tray
It is under the hood, next to the battery.
The computer behind the battery is the regulator.
It is under the hood, next to the battery
Battery disconnect or a scan tool.
Yes
Under the battery on the driver side.Under the battery on the driver side.
Check battery cables for tighteness and corrosion Could be starter solenoid
All fuses are under the hood, next to the battery.
Yes.
Under the hood, next to the battery.Under the hood, next to the battery.
An eight feet bed of a 2009 dodge will fit a 2006 dodge 2500 with a little moderation.