Heater continuously running

[tstrawic]

My first post! Seems like many of you have so much knowledge bout things!!
Have 2011 RZ2 with bluesea acr and when turned battery to combine, everything worked but heater ran con't even with key off. On I, boat started and Tige touch screen on but no lights or stereo. Heater off though!
Any suggestions??

[dom w. forte]

Sounds like the main power box internal relay is stuck on.