Skylaw

I have a 2005 S500, but because this situation arose from the design of the rear seat child restraint system, it is probably applicable to other models and years.

First, what happened was my own fault. My dealership offered to try to get the situation fixed under warranty - but very simply, it was my own fault, so I did not request that they do.

For years I have secured a medium-sized pet carrier in the back seat by looping the rear seat belt on one side or the other through a handle at the top of the carrier, tying it fairly loosely. Typically, the load has been firm enough when traveling this way that looping the belt through the top was sufficient.

However, recently there was nothing else to brace the carrier, and I looped the entire seat belt around the carrier, and then looped the top portion of the belt through the handle. The belt had more tension on it this way, and the knot pulled tight (against the buckle). When I got where I was going, I could not get enough slack to loosen the knot. Each time I tried, the belt retracted a little more.

I had to cut the handle of the carrier, hoping to loosen tension and untie it - but the takeup reel kept retracting, and would not release to provide any slack (as the front belts do).

Bottom line is, the belt retracted with the knot against the upper panel (where side air bags are). I took it to the dealer, hoping that there was a release device on the takeup reel - that would allow me to get some slack and untie the knot.

There isn't.

$600 to replace the belt (parts + labor).

The rear belts must be nearly fully fed back into the takeup reel (I would estimate about 80%) before they will release and let out again, once thay have locked. They allow a little slack, but not nearly as much as the front belts (which only need the tension released slightly in order to feed out again).

So, don't tie knots in your seat belts. That's not how they're designed to be used. Duh!

revstriker

This is used on all US cars in back seats. It's for the installation of child seats. If you pull the belt all the way out, it locks as it goes in. That way, you can pull the belt tight to hold the child seat in place. You need to release the buckle, and let the belt all the way in for it to release and pull back out.

Normally when this lock engages (when you pull the belt all the way out), you can hear a clicking sound as you let the belt back in.

Sorry you learned this the hard way.

Skylaw

Yep - it has been about 20 years since I used a child seat.