This used to be true on many cars, but the "SPARES" on the 2011 Edge are live -- they just don't have a connection to the accessory that uses that location in another market (China). Both 33 and 36 are live and perfect for plugging an accessory into. I used #33 for my Garmin Nuvi 2798 with backup camera.
The hardest part was finding a way to route the wire into the dash. I ended up enlarging the hole for the "direct sunlight" sensor right between the defrost vents.