Depending of what you need the power for, I would hesitate tapping into anything unless it's to trigger a relay or solenoid. There's also THREE different types of switched power; Accessory which is hot in ON and ACC (radio, wipers). Ignition which is hot in KEY ON and CRANK (Fuel, PCM) , and accessory which is hot only in KEY ON but dead during crank (HVAC). I would suggest running a fused wire from the steering column or from behind the radio (ACC). I wish I could help more.
'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