W124 coupe seatbelt presenter testing.

[boomtings]

Does anyone have a guide or wiring diagrams for the seatbelt presenters?

mine does not work on the drivers side (no response and in closed position), ive taken off the cover and dont know what the resistance should measure on the motor or know what the wires are.

ive googled and read many threads but cant find a thread that details the system for fault finding.

microswitch and door switch function, im going to test the seatbelt wire next.

mines a e320 my85.

 

[boomtings]

ive found the following out for the connections to the control unit on the arm:

Input plug (from car
red/yellow stripe =?
brown = gnd
brown/white stripe = door switch

brown/yellow stripe = seatbelt
(maybe easier to check this first from under seat wiring , close to airbag red connection)

black/red stripe = 12v

output plug ( to arm)

____MICROSWITCH PINS___
1st pin (closed with common when switch is open
2nd (middle pin) closed with common when switch is closed
3rd pin = common (blue wire)

For the microswitches pin1 and the common are connected (close to break!) when the switch is open and the middle pin is the opposite (close to make).

blue = common for all microswitches

yellow wire =microswitch A (1st pin ,shorts to common when switch is open)
white wire = microswitch B (middle pin, this microswitch located under microswitch A)

red and grey wire = microswitch C
(red = 1st pin,grey =middle pin)

brown microswitch D (middle pin ,microswitch located on its own on interior side)

 

[boomtings]

ive noted the following when testing,

1) red and grey wires both short when controller is connected (not sure if fault in controller?)


2) white wire , this microswitch is testing as closed, i cant see the switch but it looks like it should be closed.

My seatbelt and door switch wires are testing ok as well.

does anybody know what the red/yellow stripe wire is?

p.s model year is 95 not 85 as 1st post.

 

[brigadier]

Have a look here for complete w124 wiring diagrams. See post 10 for seatbelt presenters
Anyone hosting Supplement 14? - Benzworld.org - Mercedes-Benz Discussion Forum

 

[boomtings]

Thanks for the link..

 

[boomtings]

Turns out the red/yellow wire is permanent live, mine was broken at the junction at the x48f junction .

This is located rear drivers side passenger, in plastic covered tray and is just a bunch of soldered wires covered in rubber gunk.

I found this link useful
Help me find this positive voltage distribution point - PeachParts Mercedes ShopForum

now all i get is a little movement trying to retract.

Based on the ETM_151_20030_157_3 diagram on the link brigadier provided, the red and grey wires are on the "Retracted Switch" and dont look like they should show a short between them. As the microswitch test fine in isolation ,Ive ordered a new controller from ebay.

 

[WDB124066]

Is this the "Comfort Module" boomtings.....

 

[boomtings]

its the seatbelt butler controller and its located on the rear of the mechanism.

http://i19.photobucket.com/albums/b183/rbycc/SBP002-1.jpg

picture leached from RBYCC`s photbucket!

 

[brigadier]

Common fault that relay.

 

[boomtings]

Turns out that it was the the red/yellow wire after all.

wasted money on a secondhand presenter, i also had a dodgy connector on the seatbelt wire connection at the seatbase.

Also noted that in operation only the "retracted switch" seems to operate the system. The arm always stops before the other "return travel" and "extended switch" hit the stop ramp.

Thanks for the assistance Brigadier.

Be glad to know if my ramblings help someone in the future

 

[boomtings]

posted on wrong thread ooops!