When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
If it flashes 4 times then 2 times for a series of like 4 times you will probably either 1 need to clean the wires cause they are corroded or 2 need a new airbag sensor. Mine has done that and I needed a new sensor. The dealer wanted 300 with installation for it but I found one online for 40 bucks from fordpartsguy.com I think it is. I still need to change mine I keep having to put it off. I know it needs to be changed.
I was told its up front by the bumper. I havent got a chance to get at it but from what I was told its in the front bumper. There are a couple threads floating around about this. My internet is real slow so I cant look otherwise I would post it for you. I wrote a thread about a month ago about it. Do a search on Airbag light. I need to find it again and read it over so when I get my truck back I can look for it.
You can probably check out the Ford shop manual from your local library and in the passive restraint section it'll tell you all you need to know. It'll give you the diagnostic procedures, the location, and how to service it.