I had a problem with the trunk key mechanism in my 2001 Corolla. So I removed it and had picked up another one that worked from the junk yard, and lucky for me it came with a key. I ruined both yellow plastic catch (s) that hold the connecting rod to the key mechanism. I had to figure out how to hold the connecting rod that goes from the key mechanism to the truck latch - to the key side. In the mean time the connecting rod simply rested loose in the truck while still connected to the truck latch. WRONG. Somehow this prevented the latch mechanism near the driver's left foot from opening the trunk. So now I'm without a way to get into the trunk.
This is how I gained access to the truck with both mechanisms not working.
Find the rear ledge where the stereo speakers sit - even I could do this. Remove the two upholstery push-in grommet things. Both mine broke off - no big deal. Remove the three plastic covers to the tie down things and use a socket to remove the bolts, then pull the bolts out. Remove the rear brake light (that sits on the shelf) by gently pulling it towards you. Mine came out easy. Unplug the wire for the brake light at the junction. The hard part is removing the shelf with the rear seats locked into position. I used a screw driver to pry the lip of the shelf over the back of the seats, then the shelf came out. Not easy, just gently bend it while pulling and it will come out. You DO NOT need to remove the speaker covers. Now remove the one bolt holding one of the speakers. I took the starboard (right) speaker out. Don't forget to unhook the wires to the speaker. The disadvantage to this speaker is it that it is the side of the smaller back seat opening. Now put your arm through the speaker hole and feel along the cable that attaches to the back seat release pull knob and push the end of it away from you. This will pop the back seat and you can now gain access to the trunk. I reached in with a long flashlight and tripped the emergency trunk release.
BTW - once I hooked up the connecting rod to the key mechanism with a push on keeper everything worked fine, including my floor release.
Thanks to everyone one posts here. You guys/gals have been a huge help. I hope this helps someone !!!!