At the risk of a real stupid answer I shall dive in! This just happened to me last Thursday. Our 2000 xc wouldn't release the tail gate. We tried everything, the lock would move up and down but the door wouldn't release. My wife replaced the battery in her remote locking device and voila, open sesame. I was on my way to the dealer and thought I should test it before going and it worked. Stupid I know, but it released. Intermittantly working beforehand may be the battery going lame. Give it a try before removing the plates and making a deposit in the wrong part of town.