Ken is correct. On the older 850s, don't pay any attention to LEDs, just click lock on one remote, unlock on another within 5-10 seconds of the key thing (I believe it's 10 seconds?).
If you have the right remote with a good battery, it'll work BUT in those early years there were different PN remotes that looked the same but had different frequencies so if your ebay remote has the wrong frequency, it won't ever work. If you have one good remote, look closely at the #s on the other in comparison.
At the dealership, there's been many a time that I've had to go back to the parts counter for the right remote because I've been commonly given the wrong one and their parts info on that is also less the great too apparently.