When I turn my 98.5 dodge 2500 on and let it idle, about every 5 to 10 seconds the lights will dim and the motor gets quieter as if idling slower. The voltmeter is at 14 and it dips slightly when this happens. Is it time for a new battery or is there something else going on here?

 

Does it only do it in the morning's when it is cold? Like around 60 or less? Does it stop as soon as you put it in D and start rolling?

If so it is only your grid heater and you're fine -- the truck is just warming itself up.

 

yep mine does the same thing when it's cold. my neighbor who works at the dodge truck plant said it's normal for the reasons said above^

 

last I heard, and I may be wrong, 98.5's dont cycle that way when cold.

just to make sure. have your bat and alt checked. do it in the truck...autozone has a portable crash cart.

 

Just your intake grid heater kicking on and off. Completely normal.