First, you need to remove the glove box: Open the glove box. There are three hinge points at the bottom of the box (left, center and right). There are "tabs" on the box that slide into these "holders". Gently pull up and out on the left side of the glove box. The tab should pop out. Repeat for the center point. This should allow the left side stop pin to clear the dash slot. Repeat for the right side. You should now be able to turn the box, pull it from the dash and let it hang from the retaining cord on the right side. Note the hinge slots and tabs for reference for re-installation later.
Second, remove the black access door behind the glove box: This is an "L" shaped cover with three hinge points at the bottom and three tabs at the top. Gently push back on the tabs at the top to un-lock, rotate down on the hinge points and pull out. Behind this you will see a white plastic door which covers and holds the filter in place.
Third, remove white access door as follows or you will break the retaining tabs off! On the right side is a locking tab, gently press in and pull the right side of the tab toward you to unlock the tab BUT STOP AS SOON AS THE TAB UNLOCKS THE DOOR AND OPENS ABOUT ½ " or the tabs on the left side will break off, they are not hinged! Next, slide the door to the right to clear the tabs on the left side and remove. Note the position and orientation of the filter inside. Remove the old filter.
Fourth, install the new filter: Make sure the orientation and air flow direction are as marked and match previous filter. Mine was pointing "up", with the rigid side plate facing out. The new filter will be sitting on top of the fan, when the white door is re-installed, it has "fingers" that lift the filter into the proper location, but you may find it easier to lift the filter up with one hand and slide the door back into position with the other hand. That said, lift the filter, slide the tabs on the left side of the door back into there slots. Push the door back into original position and latch the right side locking tab. Make sure the door is sealed and back to original position and latch tab on the right is locked.
Now, reverse the previous steps to complete the task. Re-install the black access door cover. Lift up the glove box and turn to install right side stop pin into dash slot position, rotate left side into position and center box in dash opening. You will have to move the box up/down, in/out a bit to "feel" the hinge tabs properly engage the hinge slots. Once the tabs are in the slots you can push down on each side and it will pop back in place. (If you have difficulty, you may want to remove the under dash cover below the glove box. There are three tabs in the front that slide into three slots and one tab and slot in the rear. This can be removed by pulling down on the front of the panel at each side and the middle, then slide it forward out of the rear slot. Disconnect the light if required by pushing the latch on the plug and pulling it off. Feel around the hinge locations to guide the parts together).
Read more: http://wiki.answers.com/Q/How_do_you_change_the_cabin_air_filter_on_a_2006_Infiniti_M35#ixzz1NKCLa6qC