W140 Coupe Seat Belt Extenders

[alan.cockell]

Both of my SBE's have ceased to function.
They were both working OK.
I got home and got out of the car (left the engine running) to open the garage door. On re-entry to the car the SBE's extended (but I did not put my seat belt on), I drove the car into the garage and switched off. When I opened the door I noticed that the Drivers side SBE was extended (the passenger side had retracted) and refused to retract electrically.
I have pushed the offending SBE home but now neither work.
Anybody have any ideas?

 

[television]

Do try the fuses first, this is the diagram

http://www.autolib.diakom.ru/CAR/Mercedes-Benz/1997/S500/SYSTEM WIRING DIAGRAMS/6441.pdf

 

[alan.cockell]

Do try the fuses first, this is the diagram

http://www.autolib.diakom.ru/CAR/Mercedes-Benz/1997/S500/SYSTEM WIRING DIAGRAMS/6441.pdf

Both of the fuses were OK but I replaced them anyway.
Still no joy.
Where next?

 

[jibcl500]

Open the door and remove the switch as seen in the picture, the switch can be taken apart and cleaned, the contacts will be really dirty but hopefully that will be your problem.

If your not comfortable taking the switches apart I can send 2 to you pre cleaned.

jib

 

[alan.cockell]

The switches appear to be working OK as the interior lights still work when either of the doors are opened.

Do I still need to clean the switches?

 

[jibcl500]

The switches appear to be working OK as the interior lights still work when either of the doors are opened.

Do I still need to clean the switches?

The seat belt extenders take a feed of that switch, the interior light working or not is irrelevant, you need to remove a switch take it apart and clean all the internal contacts, my guess is they will be black and gummy.

My passenger seat extended started going out and back in again whilst driving I spent many hours trying to find the fault, found the switch to be the fault cleaned and all good.

jib

 

[television]

Also worth checking the micro switches in the end of the arms though having them both fail cant really be that, I think it will need a volt meter to see where the power is not going to

 

[alan.cockell]

I have now removed both switches, cleaned and checked them but still no SBE's. What next?

 

[television]

I will check to see what there is on WIS but you have the diagram for it all and it should be simple with that and a voltmeter

 

[jibcl500]

Check the fuse in the boot, its on the right side of the boot behind a little flap.

The belts extenders are triggered from the switch at the door. Also have you pressed the switch on the console to make them extend?

Theres also a sensor in the seat pad, look under the seat at the connections as the the connector for the seat pads are prone to coming apart.

jib

 

[television]

As both are affected it has to be a main power supply fault

 

[alan.cockell]

Now is the time to get the multimeter out.

Where exactly is the seatbelt extender system control module situated?

 

[television]

it is in the lower nearside C panel I think, it tells you the location of everything in the diagram that I put up

 

[alan.cockell]

According to the drawing you sent, it is "behind the right rear seat" but I cannot find it.

How does one go about removing the trim panels over the C post?

 

[jibcl500]

According to the drawing you sent, it is "behind the right rear seat" but I cannot find it.

How does one go about removing the trim panels over the C post?

I think its where the fuse box is under the bonnet, if its the part number I think it is then you cant buy these anymore as MB dont have any stock of them.

jib

 

[television]

According to the drawing you sent, it is "behind the right rear seat" but I cannot find it.

How does one go about removing the trim panels over the C post?

The control unit is where I said and 128 in the picture, I will chack on how to get to it

 

[television]

I have printed off the MB service sheet for you on this.

Fuses F3/34 and F4/7 must be good

I can send you quite a lot of info

 

[alan.cockell]

My email address is alan.cockell@btopenworld.com

 

[television]

OK some interesting things sent, I hope you fix it soon I am away from Monday night for nine days

Please edit out your address

 

[alan.cockell]

Thanks for the two pdf's. Do you have anything on how to remove the trim panels over the SBE's?

How do I edit out my address?