Originally Posted by Jbb1970
the battery is staying charged when the truck is running. It is only when I shut it off that I get the message.
The alternator runs electronics and charges the battery when your truck is running.
Originally Posted by Shaggy1970
Is the message your getting "Turn power off" or "Low battery"? If it were mine, I would hook up a voltmeter when I got home for the night and I would go back out the next morning check it again. If you have a significant drop, I would say you either have a draw somewhere or a short.
Wait 15 mins for the battery to stabilize before taking the reading at night. It should be 12.4v or higher (up to 13.2v). If it's below 12.3v, it's bad.
You can also check for parasitic drain by disconnecting the neg cable and put a DMM between the post and cable. Set the DMM to Amp to see how much power is being drained while the truck is off.