We have an 07 MKX ... original owners. I installed a hot line from the coach thru the Umbilical cord to the battery so that it would charge while driving the coach. Also within the hot line under the hood installed an inline diode so as to NOT have back feed to the coach. Without it (before I installed it) when turning the coach ignition off ... the engine keep running. My MKX battery (before the hot line) would get weak on long runs because the GPS would continue running along with whatever is hooked up when the ignition is in aux position.