On the main radio harness the integration wire for the steering wheel controls is pin 18, Lt/blue/red wire. You can program each button (vol up, vol down, source...) one at a time during programming of the interface module. The harness you have that connects to nothing may be for a trunk mounted CD changer. You're only going to have a large gray 40 pin connector and a small harness for the factory woofer. Tip: use a resistor on the OE amp turn on wire to prevent on/off pop. I can't remember the value but whatever works just test it to make sure the pop is gone.
Last edited by BAD MERC; 10-21-2018 at 10:09 AM.
'04 Silver Marauder w/ sunroof - HID lighting, JL Audio / Eclipse DVD/NAV/iPod/camera, 4.10's, 2" drop, Progard Bumper Baffle, Delete tips, Billet Pedals, BC4E dead pedal, Lidio Tune, Mach1 chin spoiler, K&N CAI, TCE lines, Super40's, tinted tails, SS Inserts, Heinous Control Arms, Real oil gauge, lighted door handles. Currently installing Eaton M112.
2004 Mercury Marauder
Born March 2004, adopted October 2005. Sold January 2012, adopted AGAIN January 2016
2,187 of 3,214
997 in Silver Birch
448 with light flint interior
304 with heated seats
336 with sunroof