I finally got into my glove box yesterday, so I thought I'd share a bit. The problem was that both the upper and lower glove box hatches were locked, even though the locking mechanism was unlocked. This had happened after the glove boxes had been locked for the first time in about three years.
I started by "picking" the upper door. Take a very thin flat-blade screwdriver and insert it into the slot between the doors where the catch mechanisms are (approximately in the middle). You can find this spot by running the blade lightly between the doors. Once you've found the spot, put the blade in on a low angle from the right side with the flat of the blade angled slightly up. Poke around in there, you'll find a hard stop against some metal, and then you'll want to pull the blade toward the seat slightly and see if you can go in further. It takes some patience (singing "Popeye the Sailor Man" may or may not be the key, but it worked for me), but eventually you'll slide the blade in and hear a nice click and the upper door will raise.
Do not be tempted to try the same thing on the lower door. The angles are not there, and the mechanism is rotated 90 degrees, making the pick damn near impossible. The upper door is MUCH easier - it took me about 15 minutes, and I had no clue what I was doing.
Once you've got the upper door open, gently remove the rubber gasket material between the doors (it's got a short fabric nap on the facing surface). It may have some double sided tape holding it down, but on my car it was all dried out so the gasket camp up pretty easily. It's a strong piece of rubber, so don't worry too much.
Once the gasket is up you'll see two screws holding the latch mechanism in place. Remove those and you'll see that the mechanism can be moved slightly from side to side. Move the mechanism as far to the left as you can and hold it in place with one hand. Now move the bottom door as far to the right as you can (it's got some play in it) and pull gently down. The striker in the door should now slide around the catch and the door will be open. If it binds, pull the door down in the middle with some force and see if it releases. There's nothing you can break, so try a real tug. Just be sure to stop pulling when the door releases or you'll pull it through it's stops.
If the bottom catch cannot be jimmied as described above, you should be able to pop the mechanism straight back out. Then you can unlock the mechanism manually. After the two screws are out, the only thing holding the mechanism is a small press-fit plastic piece, which would be difficult to break as long as you pull straight out on the mechanism. Be careful when you pull, there are two pieces of plastic that may come free.
If you are able to get the door open without pulling the mechanism, you now get to pull the mechanism anyway. Just pull straight out on it. Watch for loose plastic.
Once the mechanism is out, you will need to remove the upper glove box liner (4 screws) to gain access to the back of the bulkhead, where the lock position switch is located. When you pulled the mechanism, the two pieces of plastic that may have come free are the keeper that goes on the front side of the bulkhead and a cammed disc on a shaft. Go ahead and re-install the keeper on the position switch. There's a tab on the inside ring of the keeper, it should be set at 9 o'clock.
The cammed disc goes back into the mechanism, cam side inward. Just rotate it until it sits in as far as it can.
The mechanism cover is held by two tabs on either side. The cover is also an anchor for one end of a shaft with a spring pushing on it. You can get the cover off with out the spring flying out if you're careful. Once inside you can diagnose to your heart's content. As it turned out, there was nothing wrong with the stuff under the cover on mine. The mechanism worked perfectly every time once it was out of the car.
My problem seemed to be the cammed disc. When the mechanism is locked by the key, the cams are rotated in such a way that the catches are mechanically separated from the release buttons. When the mechanism is then unlocked, the disk is supposed to rotate back so that the buttons now activate the catches. This was not happening on mine. I looked all over for something that was broken, but couldn't find a thing. The parts that were supposed to engage to rotate the disc to the unlocked position look to me like they were designed with too much slop in them. Beats me how this thing ever worked.
I put some light oil on the parts and got it to work about half the time, but it's still not reliable.
