After an accident, your Mercedes-Benz seat belt locks up and will no longer retract. This is due to a blown pre-tensioner. To fix this problem you either need to replace the seat belt that has the blown pre-tensioner which can be expensive or another less expensive solution is to repair your existing pre-tensioner. Ther are many companies in the US that provide seat belt retractor pre-tensioner repair, and recharge service.
If your Mercedes-Benz seat belt won’t retract, but you know the car hasn’t been in any accident, read this article on Common seat belt problems and solutions.
Mercedes Seat Belt Locked after Accident, Fix
If you have been in an accident where the seat belts locked and maybe your airbags deployed, the pre-tensioners almost always will ignite to help retract and tighten the seat belt during a collision. This is by design to minimize passenger injuries.
Here is a picture of two different seat belt retractors which have built-in pre-tensioners.
A pre-tensioner may be on the other end of the seat belt as well or part of the seat buckle.
You will need to remove the pre-tensioner from your Mercedes-Benz. Removing your pre-tensioner is very easy and straight forward process. Rember to disconnect the negative battery before you disconnect the pre-tensioner.
For example, let’s look at how you can remove a seat belt retractor with a build in pre-tensioner.
Remove the door trim and molding to expose the retractor.
Disconnect the electrical connector from the pre-tensioner. There are two small tabs on the connector that you need to press before you can pull the connector. Otherwise, you will damage the connector if you force it out.
Remove the bolts that hold the retractor in place.
Remove the bolt for the bracket at the top of the b pillar.
Remove your seat belt retractor.
Mail your retractor for repair to the company of your choice.
If you don’t know of one, check out these vendors that offer: Mercedes Seat Belt Pretensioner Rebuild
The advantage of repairing your existing retractor isn’t only the cost benefit but also the fact that you will need to code your airbag to your Mercedes-Benz. There is a very good chance that you will need to clear the airbag/srs codes after the installation. You can read and clear Mercedes-Benz SRS codes yourself using a multi-system airbag scanner such as iCarsoft MB II. If you want to learn more about scanner that can read Mercedes-Benz specific codes read our article on Best Scan Tools for Mercedes-Benz cars.