I am accumulating the parts to do a DDIN install in my 15 Connect XL LWB. It has the steering wheel controls and 4" backup screen so I'm debating if I NEED a harness adapter to keep the backup screen. Crutchfield has the Crux one for $99 (kinda pricey for an unfinished harness) that supposedly retains steering wheel control and the 4" screen but some are saying it puts a draw on the battery. I have no desire to make my vehicle, which is parked most of the time, have a dead battery. I plan to manually cut and splice the wires with crimp nuts rather than buying a harness that isn't even plug and play. If I leave the wires from the OEM harness going to the 4" display will it still work or does it pull its power FROM the factory head unit? I haven't done audio in a newer style car before, it's all been pre 2005 era so easy peasy. This new stuff looks like a nightmare lol! Any suggestions on other places to find a harness that won't drain my battery or install tips would be appreciated.