When I bought my X5 a few weeks ago, the owner told me one key was dead from lack of use. I drove an hour and it still would not lock/unlock doors. I was pissed and figured I had to buy a new key.

After reading this I went out to the truck (11pm) in the rain and was able to reprogram my key!!! Thanks.

ps. These steps are WAY easier than reprogramming the fob for my e36 - it's an insane process.