Previous owner installed one on my 1500 in the Right saddle bag.
Basically the same as this.
The leads connect directly to the battery and the lighter end of it just sits in the bag with the wires running through the same hole the Aux air hose comes through. There is a rubber boot over the lead connectors. I don't smoke so the location is fine and good for using to charge cellphone batteries, etc.
Don't know about the '05 but on the '08 you can plug-and-play in the left and right front pockets and in the trunk (take the trunk lid lining loose and you will see it. Keep in mind that these are only good for 3-5 amps. Anything else and you might fry a circuit or at least a fuse. I ran the one in the trunk under the seat and straight to the battery and wired in a 15 amp fuse on the positive lead so I could use if for my air compressor.