Phil P2

Hello all It has been a while sense I posted here for several reasons. Shortly after ordering a 2021 Duramax 3500 to replace my 2009 the engine in the 2009 stated leaking compression in to the cooling system. So being busy keeping that on the road without spending 6 or 8 grand on the engine I haven’t had time to post here. I finally got the 2021 I ordered February 2021 came in March 22 as a 2022. It has been in the shop for problems with the DEF system every month sense I got the truck. They finally got it working correctly. Now my problem is I assumed the 12V power receptacle was protected by a fuse, however it melted the plug and receptacle. Now I am having problems with Android Auto that requires the data cable between the cell phone and the truck. My question is how do I gain access to the back side of the USB and 12V power plugs to see if there is wire damage? Phil P2