These are the Nissan-Supplied instructions for the In-Cabin Microfilter. They are somewhat generic, and were not 100% accurate to my car. The only difference was that my car did not have the "Glove Box Finisher". Besides that, everything else was correct. Perhaps the Glove Box Finisher was eliminated in later 5th-Gen Maximas?
I bought my filter at a Nissan Dealership. The cost for one of these babies is $58.74!!! Cheaper deals can probably be had on the Internet.
Nissan recommends changing this filter approximately once per year. This procedure is not listed in the owner's manual, as Nissan prefers this operation be dealer-installed. With only a Philips screwdriver, if you are the least bit competent you can do this job yourself and save the money. The filter alone is expensive enough!!
Start by removing the glove box latch. 2 screws and it's out.
Next, remove the 4 screws holding the glove box in place. There are 2 at the top and 2 at the bottom. You will have to disconnect the glove box light, and the air bag connector. Both come off easily, and the entire glove box can be removed.
Once the glove box is out, the next step is to pop off the metal clip holding the white filter cover in place.
Now the filter can be slid out. Apparently, the microfilter put in at the factory is a single piece, and does not look like the factory replacement filters you will put back in. In fact, the replacement filters look much nicer (higher quality). This picture shows the empty hole where the old filter was.
This side-by-side shows the stock filter removed on the left, and the replacement filters on the right. I was quite amazed at how dirty this filter got. The replacement filters come in two pieces, and have plastic holders that enable them to slide into place more easily than the original filter.
My filter had all sorts of black dirt, crud and leaf pieces in it!!! And I keep this car garaged, and never drive it in the rain (if I can help it).
The easiest way to get the new filters in is to put one in at the bottom, then once it is in, slide it up into the top position, since it is difficult to get the proper angle to put the top one in directly.
Here is the completed filter installation, with both filters securely in place. Replace the white filter cover, glove box, reconnect the light and air bag connectors, and this installation is complete. Ahhhh, fresh air to breathe once again.
Thank you Greg!!