Can you tell me how to locate the reverse wire is in the shifter area.

Also can someone tell me if their eclipse unit drains battery fast.I turned on my ignition and was testing out the unit while installing(it was on for about 20 mins and started blinking.I thought something was wrong and then when I tried to start the car it seem battery was running low.
I am sure I wired the unit right.
is there something wrong in wire the eclipse cd changerand the eclipse unit power wire(yellow wires) to the same 12v location? that shouldn't be a problem right? because even to joined together, both wires should be receiving 12v equally,right?(lil. bit of knowledge fromhigh school physics
thanks