I can believe it. There's a pre tensioner in some Fords. It's built into the buckle in the seat, and has a charge in it, like an airbag. It's suppose to tighten the belt on you on the right impact. AFAIK, seatbelt assemblies must be changed in sets. I have also seen airbag issues and ABS issues crop up with related electrical problems. I had an airbag light on a Chrysler minivan calling out multiple codes. Right after that, it wouldn't start. The battery was wood. I replaced the battery, and all the lights went away.