Boost, House Disconnect and starter solenoid in my battery bay - 2007 Allure.
Drawing shows effective Coach #31446, ISL400. Not sure if applies to your 2009 500ISM.
Hope this helps,
Towr: 2007 Country Coach Allure 470 - 37 Sunset Bay Cummins 400 ISL, Coach #31563
Toad: 2016 F150 King Ranch - 3.5L EcoBoost 4x4 Supercrew (curb weight 4,775 lbs)
Toad: SOLD 2007 Jeep Grand Cherokee (yes, it has a Hemi) (curb weight 4,720 lbs)