Why does the check engine light on a 2004 dodge ram equiped with a 5 speed aut and 5.7 hemi keep coming on the codes read low voltage and the truck has 25000 on it?

Answer 1

There's a potential that your alternator may have a failing voltage regulator, or may not be producing proper voltage. Take it to a repair shop for dynamometer testing. What the shop will do is connect the alternator to a bench, rotate it at a specific speed, and test the operation of the charging circuits.

Another potential is simply that your battery cables are dirty or corroded, or you've got a faulty ground circuit between the engine and the frame/battery.

The former will eliminate the potential for needing a new alternator, the latter is a good way to make sure you aren't experiencing other electrical problems related to poor grounding.