Originally Posted by Tfryman
But the question isn't what is powered by the chassis battery; the question is: What is continually powered by the chassis battery when the ignition is off that could be draining the chassis battery?
This is a hard question to answer since it varies from model to model and within a model line.
The computer(s) that Ford install for the engine are powered all the time for sure. on our Axis the camera splitter is powered all the time.
There is also line from the parking break and something that looks at if the coach is in park that feeds the camera system to turn on the radio.
Batteries also self discharge about 1 to 3 percent a month.