I just finished removing the navigation unit from my 01 QX4 not too long ago. I rewired it to use the climate control system that the non-nav vehicles come with. So, a couple of notes that I came away with:
1. I didn't use another year climate control unit because I noticed some of the voltages used to communicate engine temperature and such were different, to a degree that the readings would have been WAY off. I’m not sure exactly what the unplanned side effects would have been so I decided to simply sidestep the whole question. There were also a couple of missing pins in previous years’ units (I think ECM Comp and Comp On)
2. I wasn't able to buy a climate control unit that had the harness connector or wires, but I had a bit of luck in that I found the perfect connectors and wires on eBay listed as "00-02 Nissan Maxima AC Heat Climate Control Wire Harness". It ended up being short a terminal/wire, but I was able to Mickey Mouse it together with no problems. I’m willing to bet money that the connectors were used on other vehicles, so doing some larger sweeps of eBay may yield better results.
Also: I'm selling my old navigation unit for $300, shipping included. I'll include the navigation disc (of course), and the climate control box.
@fannan73: the wires coming directly out of the navigation unit don't do anything to directly control the climate. The wires run to a black climate control box which is mounted near the floor below the stereo. It's about the size of 2 cigarette packs. The wires coming out of it are the ones you're looking for. The black box will be replaced with whatever climate control unit you choose.
Here’s the wiring chart I used during my research and implementation. The colors of the wires can be found in the FSM if needed.
https://docs.google.com/file/d/0B3ZOuhE ... E1VWExDX3c
I used the bezel from a non-navi QX4 of the same year, so there wasn’t any fabrication needed. The only bit of custom work I had to do was make a cutout to fit around the stereo. The location of the stereo in the cutout wasn’t totally my choice; I used the bracket that was already there and that’s where it ended up. The huge perk to the placement was that I have the option of drilling holes where those Pac-Man-looking circles are and mounting gauges. The triangle portion of the Pac-Man points to where the middle of the circle is. This will be useful if you end up drilling those holes.
https://drive.google.com/file/d/0B3ZOuh ... WxPOHZrVnM
You’ll notice the template is inverted; this is so you can print it out (it’s scaled exactly to size, so don’t let the printer scale it), glue it to the wood and get to business with a jigsaw. The printed and glued paper will end up being on the inside of your console, so the opposite side can be laminated or painted like I did. Hot glue worked fine for mounting the cutout in the bezel.
Voltage and oil pressure gauges will appear there at some point in the future. I ended up swapping out the light wood for something darker.
This project ended up taking a number of weeks of studying the FSMs on the bus and scouring eBay, so take your time and make sure you understand what you’re doing before pulling things apart.