2008 Edge SE with manual A/C and 26,000 miles:
Thanks for the information on the cabin air filter. I went to look for mine yesterday and easily located it behind the glove box. After opening and unloading contents of the glove box the first step was to detatch that string on the right side of the glove box, but that was very easy -- I just maneuvered the black disk on the right side of the glove box down into the empty cut-out circle below it and was able to push the plastic disk through the right side of the glove box and that disconnected the spring-loaded string from the glove box. Then, with the glove box open, all I had to do was pull inward on both of the upper sides to allow the stops to get past the hole in the dash, after which the entire glove box fell right out onto the floor. There are 3 or 4 hinge points at the bottom of the glove box on which it pivots.
With the glove box removed I could see the black plastic door covering the cabin air filter. I tried pushing the small black plastic lever on the left side of this door over to the left but the door wouldn't come off. Then I got a slotted screwdriver and inserted it into the space next to this little latch on the left side of the access door and the door popped right off. Inside, I could see only a screen, not a filter. It was a simple matter of pulling the screen out, cleaning it using the sprayer in the kitchen sink, drying it with paper towels and reinstalling everything in the reverse order of disassembly. Since this was the first time I did this job it took about 30 minutes.
This was the first time I'd cleaned this screen in 26,000 miles. It was dirty, but not unusually so. I think I could do the whole job again in under ten minutes. I don't think I would ever bother with buying and installing a filter in addition to, or in place of, the screen that's already in there.
Later on, I looked at my owner's manual to see what it had to say about the cabin air filter. On page 80, under 'Climate Controls,' it states:
CABIN AIR FILTER (IF EQUIPPED)
The cabin air filter element is designed to reduce the concentration of airborne particles such as dust, spores and pollen in the air being supplied to the interior of the vehicle. The presence of a particulate filter element provides the following benefits:
Improves your driving comfort by reducing particle concentration.
Improves the interior compartment cleanliness.
Protects the climate control components from particle deposits.
NOTE: A cabin air filter must be installed at all times to prevent foreign objects from entering the system. Running the system without a filter in place could result in degradation or damage to the system. If your vehicle is not equipped with a cabin air filter, a protective screen has been provided in its place and must remain installed at all times.
The access door for the filter is located behind the glove box. For replacement intervals regarding the cabin air filter, see the scheduled maintenance information. For more information regarding your filter, see yoru authorized dealer.
I looked in the 'Scheduled Maintenance Guide' and it tells me to replace the cabin air filter (if equipped) every 15,000 miles. I guess I'll just clean the screen at that frequency.
