Anyone with seatbelt problem solving experience
 

This morning I pull my seatbelt and it comes right out, no resistance, then no retraction at all. Completely normal yesterday so I assume something broke inside. Passenger works fine so unlikely to be an electrical problem.

I pulled the rear trim off (this job sucks so very much) to access the seatbelt retractor which felt like it was at the very centre of the car.

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I pull it out and the white plastic guide on the top is flapping around so I place it back into its grooves.

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From others posts I did not remove the green electrical connector. I assumed it would cause havoc as I guess it is part of the emergency seatbelt retraction system and would give a SRS fault? Maybe someone can confirm.

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Anyway I believe this is the mechanism that retracts the seatbelt.

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The black plastic connector turns without any resistance in both directions. Would this be the likely cause? I know if I open it a whole pile of crap will explode out so if someone could confirm my logic first it would be much appreciated.

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For anyone facing similar problems, these thread were useful:
http://www.benzworld.org/forums/w209...etracting.html

This one has the bulletin Glyn posted but otherwise not the most helpful
https://mbworld.org/forums/clk-class...etracting.html
Right at the bottom (post 22) Rodney has posted the WIS documents to get the trim off.
https://mbworld.org/forums/clk-class...g-anymore.html

I had the same thing happen to my car about a week ago. Didn't try solving the problem myself because they implemented new driving laws and the cops are all over the place. Just went ahead and bought a used unit and replaced the whole seatbelt mechanim

and yes that green connector is a SRS system plug. If you do reach a point where you need to unplug it remove the battery connection for at least 30 minutes then unplug the green connector and you shouldn't get a code once everything is connected again.

Thanks for the response. Did you pick up your replacement locally or on ebay? I got told $799 (~US$600) from the dealer for a new OEM so that isn't really an option right before going on holiday. I would prefer a new one but a refurbished used one would be fine. I haven't been able to find it on the online parts stores- pelican parts, parts.com etc.

I seatbelt is lying on the back seat and plugged into the front seat to stop the beeping. It might be like that for a few weeks if I have to import a replacement :confused:

No question about what went wrong and if I can fix it.... lots and no. The spring housing cracked and the string broke. That string is quite thin but very very strong.
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great that you took it apart! always wondered how it works. Actully i got it locally (no ebay here, sadly) paid 150$. it used to be 50$ but with the new strict laws seatbelts are in high demand. I cant understand just how many people had seatbelt mechanisms that were broken that suppliers felt they needed to raise prices. I cant drive without my seatbelt, feels weird.

FYI, unplugging the green connector (as with any of the SRS connectors) is no problem as long as the ignition is switched off. But if you feel better about it, you can disconnect the negative lead on the vehicle battery (no need for any 30-minute delay). Also, make sure NOT to switch on the ignition with this green connector (or any SRS connector) unplugged. If so, you'll trigger a permanent SRS fault that can only be cleared after reconnecting the harness and using specialized equipment (such as the dealer's SDS system). Generic OBDIII code scanners won't reset MBZ SRS errors.

thats weird, I've unplugged the SRS connector many times in many different locations (with no ignition) in my C and my CLK and they always result in an SRS error because i'm not patient enough to wait 30 minutes. I dont remember where i read that waiting 30 minutes with an unplugged battery will not cause an SRS error, it was somewhere on this forum.

Thanks for the advice. I purchased a replacement second hand belt from ebay. Hopefully will arrive in the next 1-2 weeks, it shipped early today. I will disconnect the battery for fun, I see no reason to risk a visit to the dealer. I have avoided having a relationship with their service department thus far, parts department not so much.

And today my heated seat would not turn off using the switch but did with the ignition. Then it wouldn't turn on again after work. And parking sensors have a mind of their own 5% if the time :-( it seems my car saved all the problems up to take a dump on me in one week.

Finally got back from holiday and the seatbelt had arrived. I put it in (took 5 mins) but have not put the car back together around it. At least I will have a operating seatbelt until this next weekend when I will have a chance to look at it in the daylight hours. I will have to look at WIS again and remember how I pulled the trim off.

I took the fob out of the ignition and did not get an SRS code when swapping from the old to the new unit (did not disconnect battery). To get the wire out gently pry up the clip on top with a screwdriver and it pulls gently upwards.

Otherwise despite looking clean, the parking sensor problem was completely fixed by giving them a good wipe with soap and water. Also ordered new carbon fibre heated seat elements (universal and 12V) so they should never break again- US$49 off ebay for all 4 (2 lower 2 upper for both front seats).