millertyme

I just picked up the car a couple of days ago, and have everything working except for the power mirrors. the po had replaced the passenger side with a much smaller mirror, and i was hoping that was the issue. i picked one up at a local recycler, and went through the trouble of painting it prior to installing it. I installed it tonight, and still nothing. then i looked closer at the plugs. the short plug has 5 wires from the car harness, and the mirror only has 4. and only one of them lines up. could it be that the car has memory mirrors, and that is the reason for the difference in the wiring.
BUT, in saying that, i then took the drivers door apart, and on what i believe to be an original mirror, the wiring is the same. 4 from the mirror, and 5 from the car.
any input would be greatly appreciated.