If you don't want to go to the dealer, which is probably why you're here, find a mechanic with a scan tool that can read Ford airbag codes. They start with the letter B. It might cost you some money, but it won't cost any more than Ford wants, which will probably be about $90. If you're friendly sometimes you'll get the code for free, like I got at a Midas recently. Once you have the code, post it here. Not much you can do to troubleshoot without it.