i recently bought a sable and the rear drivers side door won't unlock (the window on that door works) I have a keypad lock and I don't have the code nor the owner's manual, what can I do?

You say "won't unlock" then mention the key pad, so what exactly is the problem? It won't unlock with the keypad? It won't unlock with the hand operated button on the door? You need to narrow it down for the proper help. If it works from inside by hand, then you need to replace the electric lock activator inside the door. If it doesn't work at all, you need to get the door opened and apart to see what the problem is. As to the key pad lock code, if you are lucky, it is still where it should be - in the trunk on a sticker on the underside of the trunk lid. I wasn't as lucky with my 96 Sable when I bought it. Someone removed the sticker, and I cannot locate any numbers physically, anyplace in the car, and calls to Ford?/Mercury were useless because they have no info going back that far according to everyone I spoke to.