main switch has to be set on both batteries to crank

[Rifleman65]

I changed batteries this year, had starter issues, replaced starter but would only crank when set to both batteries. There aren’t many wires to get crossed when connecting batteries. Anyone have a quick answer for me by chance?

[lee]

Did you check the voltage at the batteries?

[chpthril]

Two likely scenarios. Switch has failed or the main cranking battery has no voltage to the cranking circuit,

#1. A quick voltage check on the back of the switch will test the switch. Switch OFF = voltage on one #1 post and one #2 post. Switch ON = voltage on all 4 of the switch posts.

#2. Common cause of no/low voltage is that a battery cable has been left disconnected. Either the ground or the smaller alternator feed from the isolator.

[Rifleman65]

according to the touchscreen my cranking battery is 14 and house is dead basically, 12v and brand new. I have issues with the house battery getting low and the screen shuts off. I’m pulling it out of the water this weekend and fix everything