adotomov

Hey guys, I have a quick question regarding seat belt sensors. If I am not mistaken, I should get an alarm going if I don't put my seat belt on. Same goes for the passenger seat. However, I don't get any indications that I am driving with unhooked seat belt. Do you know where the sensors for that are? Is it easy to change them and should I call MB dealer for the parts?
Appreciate the help!
Cheers!

Plutoe

When you start your car do you notice all the individual function lights go through a test---they light up and then go out------do you see the seat belt function do that?

The sensor , as you call it, is a switch and it is apart of the female buckle! The switch may be bad.

Although only sold in pairs the set is cheap, however in most cases the seats have to be removed and that's loads of labor expense.

However before I would go through that expense, find an Indy with a copy of DAS Xentry----he can quickly test that circuit and determine what if anything is faulty.

By the way, what country do you live in, not all country versions have that option!!

adotomov

Plutoe, thanks for the help. You are like the most helpful guy on this forum so far.
Yes, the seat belt light turns on on the dashboard and it is actually the last one to turn off after I start the car. I have some suspicions that the previous owner somehow altered this so it won't annoy him when driving without a seat belt, but I always drive with a seat belt on and it annoys me when it is not working.
So, are you saying that I have to buy the whole buckle? Is there a way I can check if they didn't intervene somehow with the switch? Maybe it is an easy fix. How does it look like?

Plutoe

If in fact it is a faulty buckle switch, MB only sells sets.

A quick test is to look under both seats for a loose two wire connector that is not plugged into its socket.

adotomov

Okay, I checked under the seat and there is what it looks like a 4 pin green connector with two cables disconnected from the socket. Unfortunately I don't know what this cable does and where am I supposed to plug it. Any help on this one?

Plutoe

Neither do I----I do not have a wiring diagram for your car.

Is there another SAME,not simular, connector under the other seat that is connected

adotomov

Okay, I did some more digging under the seat and what I discovered is that there is a three cable connector plugged into a socket. Two of the cables are pulled out and are connected with what it seems a bridge. I am assuming that the one cable still in the connector is the one sending the signal to the computer. The other two are the power cables. Whenever you put your seat belt on, the switch closes the circuit and the third cable sends the signal that the belt is into the buckle. If you don't put the seat belt then the circuit is open and the computer doesn't receive anything from the module and signals that you should put your seat belt.
I am kind of trying to reverse engineer what they did here and I am completely not sure if this is correct, but if it is, this is a pretty clever way to remove the seat belt signal anyway

HD Rider

I realize this is an old thread but...
Did you ever find a solution to your issue. Mine is just the opposite. I get a seat belt chime and light even when all belts are buckled. I have narrowed the problem to the drivers side buckle and would rather disable the switch than spend the $$ to RR the seat and belts.