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2004 CLK500 AMG Package
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Discussion Starter #1
I posted this a while ago But it seems no one can figure out whats going on and im trying not to go to mercedes dealer because they rape everyone =\

I have a 2004 CLK500 my SRS Light came on couple months ago out of no were and i happen to look under my passenger front seat and 3 wires were broken... my friend cliped the harness wires and re-spliced them back together ... couple of the wires went to the heated seat the others im asuming were for the airbag? or something to do with the SRS System it self...

We hooked up a computer to it and it gave us this fault code:

B1037
Ignition Chk R12/21
Right Front Side Airbag
Ignotion Squib
High Resistance

Does anyone know how to fix this or has had this problem before?

Please help :(
 

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Discussion Starter #2
Also ... After we spliced the wires back together again we reset the code with this computer and it went off a few hours later it returned... So im not sure if that info helps at all or not..
 

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2004 CLK 500, 2011 C300 4Matic
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My CLK had deployed airbags when I bought it, and I did the work myself, so I'm somewhat familiar with the system, although by no means an expert.

An interpretation of the fault code you received means that the explosive circuit for the airbag (not your engine's ignition) has too much resistance in the wiring for the squib (the nitrogen gas) to deploy. The fix is to locate the source of resistance in the wiring circuit. If it were my car, I would be tracing the wiring from the airbag in the passenger seat to where it enters the dash; I'm sure you will find the problem in that section of the wiring. There is a connector, I believe it is located in the right side footwell, that may have jiggled loose. It's likely a loose connection, not a broken connection since you were able to go for a few hours before it returned. A broken wire would have set the SRS light off immediately. Also, accolades to your buddy for helping you out. I would solder those wires together. If a wire crimp was used, that could be the source of the problem too. Stick to it -you'll sort it out.
 

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2004 CLK 240 Coupe
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11,377 Posts
Does anyone know how to fix this or has had this problem before? (
There is X55/4 passenger seat contact strip under the seat.

Several items that can affect SRS are wired through there, eg,

S68/4: passenger side seat belt buckle restaint system switch.
B48: passenger occupied & child seat recognition sensor
R12/21: right front side airbag ignition squib.

If you are really foxed, I can post a wiring/circuit diagram that might help here.
 

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There you have it. It appears that the wiring resistance problem is with the connection beneath the seat. It's too coincidental that you're getting a code for the airbag's R12/21 ignition squib, and that the R12/21 wiring goes through the X55/4 contact strip beneath the seat - the same area where you found broken wires. Focus on either a poor connection on the re-splice (no offense to your buddy). Undo your buddy's previous work and solder those spliced wires together. Also be on the lookout for other wires in that X55/4 contact strip that may appear to be fine, but have been compromised by whatever cause your wires to break in the first place. Gently tug on the wires to ensure they are secure in the connectors, make sure that connector's contact are clean, etc.
 

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Discussion Starter #6
Thank you guys for all your help and information... :)... I have 1 more question thou the wires that broke a few of them are brown and the others are black with a purple stripe and one is all black... is it possible he connected them in correctly? he said that the "brown" on mercedes is ground... im wondering if my whole problem is coming from those wires in general? and he crimped them together yes and then put wire caps on and crimped em with the barrels.. not sure if this is the correct way to do so... but i tried rewiring messing with it like 3 times now.. and i keep goin back to my mechanic to reset it i guess im making him crazy lol
 

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2004 CLK 240 Coupe
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v1sionz

This circuit diagram of the Airbag Control Unit from the WIS should enable you to sort out your damaged wiring. You should be able to print the pages out. Some of these circuits are checked for continuity by the diagnostic system on switch-on.

The wire colors are shown in abbreviation eg, Bn/Pk is a brown wire with a pink stripe. Bk/Rd is black with a red stripe. Sometimes the colors fade so bear that in mind. Brown is the wire color MB use for earths, and they go to the nearest chassis common earth point, which are all termed W.

pdf Page 1 covers the wiring of S68/4 via X55/4 to N2/7 (pass side seat belt buckle restraint system switch)

pdf Page 2 covers the wiring of R12/21 via X55/4 to N2/7 (right front side airbag ignition squib) ##

pdf Page 3 covers the wiring of nothing of interest to you here.

pdf Page 4 covers the wiring of B48/3 via X55/4 to N2/13 (belt tension sensor) Also X30/7 is a voltage supply to elsewhere.

## However, page 2 has an error (imo) and R12/20 should be R12/21, and vice-versa. This is obvious when you consider that X55/4 is the front passenger seat contacting strip, and X55/3 is the driver's side. Also, W28/1 is ground left, and W28/2 is ground right.

At R12/21, I'm not sure why there are 3 pins shown, unless pin 2 is connected to a screen over the wires. The connector case is shown connected to Earth. W28/2 (should be)

The circuit diagram is more complicated as it cover both coupe (shown in U611 box) and cabriolet (shown in U23 box)

As said above, solder the damaged wires together and wrap the new joint with insulation tape. Confirm that any wires you think are earths by using a test meter. :thumbsup:
 

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That schematic should help. Also know that if the wires that were broken go into a yellow connector, those are SRS wires. That is the color used to delineate SRS wiring from other wiring on the car.
 

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Discussion Starter #9
Thank you guys so much you have no idea! and no the yellow connector wires did not come apart or break for that matter.. the only ones that did were those brown and blacks.. or brown with stripes i should say being that the color has faded... i will look at this wiring diagram and go from there to trouble shoot it :)
 

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If none of the broken wires belong to the yellow pin connector beneath the seat, then it may just be extremely coincidental that you have broken wires in the same location where the ignition squib wires are routed. Of course ensure that yellow pin connector is secure, but as I indicated earlier, trace and examine the wiring going to/from the airbag until you find the loose connection.
 
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