If youre talking about a completely base model, then I would doubt if it had any harnesses at all for what you claim there would be. Nissan wouldnt bother prewiring it if its just a base, unless it had other power options (windows, locks, mirrors) done already.wow. Well.... I wanted power locks and windows, etc, so I got the S. Some people buy aftermarket stuff, and do it. The best way to start, in my opinion, is to see if you have the harness in the door, or see if you need it. Same for the mirrors, and the mirror switch. See if theres a connector behind where your mirrors switch is, or some where around there. It seems that the S and SL trims have some prewired things. And im curious if maybe, just maybe, so is the power package, or at lest the main harness wires. My thought is that you will need to buy the harnesses for the doors and it will plug into the main plug located behind the drivers kick plate, under the carpet. But I could be completly wrong about everything, and you just have to go to a professional, or buy an aftermartket kit. But it also seems that the prewired things in the S and SL require the power package for S, or convience package for SL. Hope this helps.