I have a 2018 THOR Siesta 24SS which is built on a Mercedes Benz Chassis. I traded in my 2016 Winnebago ERA which was also built on a Mercedes Benz Chassis. For some reason the THOR does not have a battery boost switch which would allow me to boost the chassis battery with power from my house batteries in the event my chassis battery was dead. I contacted a THOR authorized shop and after they researched it, was told that Mercedes would not authorize Thor to install the battery boost switch. I then contacted my original THOR dealership and talked to the service department.They were surprised that my MH did not have the battery boost switch. They then checked their lot for both the THOR and Winnebago units built on the MB chassis. The THOR units did not have the battery boost switches but the Winnebago units did have it. So they said they could add the switch/solenoid and cabling to my THOR. They are ordering the switch from Winnebago and will be installing it. They liked the switch set up from Winnebago as well as the placement in the cab.