Hi ncgirl,
Cuco and jazz are correct, if it's under warranty then the manufactuer is responsible for correcting any defects thru one of their dealerships.
How ever, if it's a late model vehicle that the warranty recently expired, you may have a chance at getting them to repair none the less.
Because it's such a safety issue, they may be willing to repair or replace if it's deemed a defect and not caused by abuse.
You should speak with the service manager of a local dealership about the issue, ask him or her if they will contact the manufactuer on your behalf for assistance.
If they are unwilling to help you should contact the manufacturer your self by calling their toll free number, ask to be speak with a consumer rep and explain the situation.
Manufactuers will sometimes help a consumer whith such issues, even after the warranty has expired (I Know--I was a service manager for 20 years)but it depends on each unique situation.
Never hurts to ask--I've included a link in the resource box for phone numbers
Jerry
http://www.usedcarwise.com