Leather

Hi everyone,

Just a few weeks ago, I got my 2004 Mercedes CLK320 Coupe.

Back story: (skip reading if you only want to see the error codes)

I got the CLK for a good price (about 2-4k below the avg. sale price on Craigslist). The person who sold it to me knew it had a lot of small issues that they simply didn't care about fixing. The previous owner didn't seem to care about keeping the car in ideal condition; he did the minimum expected maintenance, and nothing more. He even used regular 87 fuel exclusively! Yikes! Already, I am taking MUCH better care of the car- but probably because my income is significantly less than his, LOL! I can't afford a trip to the dealership. This car is my most valuable possession, so I'm treating it like gold, because to me, it is! I've already fixed half of what the car needed: put new Continental DWS tires on myself, gave it an oil change, changed the filters (the cabin filter was at least 3-4 years old - black as dirt!), and other maintenance stuff.

Fault Codes

I've got an iCarsoft i980 off ebay for $100. The car has 2 warning lights - the SRS light, and the "Third Stop Light" (the center brake light). I am both electronically and mechanically abled, so I'm confident I have sufficient knowledge and prior experience to fix this.

I've searched the brake light code, and didn't find anything on here, so I'm just looking for help and suggestions, if anyone is so kind to provide it

Here are the codes:

[SRS]: B1035 - The resistance value in the ignition circuit containing component R12/20 (Left front side airbag ignition squib) is too high.

NOTE: I've seen 2 threads on how to fix this SRS code, but I want to be sure I'm doing the right thing. In those threads, it's suggested that the cable (with yellow plug) under the left door sill needs to be shortened to reduce resistance, and soldered back together. Does this sound correct? I've read the procedures, I just want to make sure this is the right thing to be doing for this error code. If so, I'm comfortable performing this.

[Third Stop Light/Center Brake Light]: B1056 - Component E21 (Center high-mounted stop lamp) has Short circuit or open circuit

So this is the one I need some help with. I searched, and haven't really found much on how to fix this. To be clear, the center brake light appears to work about half the time, often in reverse. But for the most part, the center brake light never comes on, at least when the car is in 'Drive.'

Any suggestions on where to start? Anyone with a technician's manual have any suggestions?

Any help would be greatly appreciated.

Thanks!

DanielFD

congrats on the car! sometimes the SRS codes can be cleared and they just simply wont come back, other times theres a problem with resistance as stated in the code. This usually means a squib was fired (during an accident) or the plug isn't connected. I'm not sure about the location of the squib but when you do find it compare its size with the right side of the car. If the left side is shorter then the squib has been fired and you'll need a replacement part. The Third Brake light, make sure the connections are good no stripped wires and such. The other most possible solution is your brake light needs to be changed out completely, they often burn out resistors and then begin sometimes working and sometimes not working.

Leather

Thanks Daniel, this information is very helpful.

1. I tried clearing the SRS code with the iCarsoft tool, but the SRS light comes back within 2-3 seconds. So, it sounds like the resistence error is real. What do you think about stripping/soldering the wires in the door sill, as suggested? I guess the technician's manual says that the fix is exactly that. Should I try it? If not, do you know what part I need to replace, and where I can find one?

2. Where should I look to troubleshoot the center brake light wiring? Are there any pictures/videos/diagrams you can point me to? For example, pictures/video of someone replacing the brake light and/or wiring? I looked around, but couldn't find too much.

Thanks again! I don't have nearly enough money to go to a dealership, so I appreciate the help.

eteller

I'm going through a little different problem with warning messages. The car thinks my third brake light and right side mirror turn signal are faulty. They both work. Replacing the third brake light fixed that issue so I have the turn signal on order as well now. BTW the third brake light is $104 OEM on Amazon.

DanielFD

to be completely honest i havent seen the front squibs before, I have seen the rear squibs though and when they are fired they give off that code to the system. Visual inspection as i said before is preferable. putting in resisters isn't a fix, its a workaround that may be dangerous. by installing resisters your tricking the SRS into thinking the squib is working fine and isn't fired. the squib pulls your seatbelt in case of an accident. it wouldn't be wise to disable such an important safety feature. in the case of the third brake light as "eteller" stated its most probably the third brake light that needs replacing. to get to it and inspect you'd have to remove the inside linking on the trunk(just from the back, where the third light is) its pretty simple when you take a look on the inside of your trunk. Its just held in place by a few pins that you can remove with a flat head screw driver. you will most probably need torx screws to remove the third brake light in case you want to replace that. so buy a cheap set u'll be using it a lot if you plan on replaring your car yourself.

and for your info. Barely anybody here repairs their car at the stealership. even if i had the money myself i still wouldn't do it. find yourself an independent specialist indy in case you need some big repairs in the future.

Rudeney

I get this error periodically on my CLK cabriolet when I leave the seat folded forward on a hot day with the top down. It pulls on the wiring harness and is gets a slight disconnection and thus the error. I have to manipulate the wiring harness to gain some slack, and unplug and replug all the connectors, then reset the code.

jwb007

Hello Everyone,
while applying leather/vinyl protector to the interior of clk cabriolet. i had the top down and i keep moving/tilting forward both front seats to gain access to rear. upon completion, the SRS warning came on.
From the task i was performing. could i have had unplug a wire harness from under either seats?
Any and all suggestion and remedies, will be greatly appreciated.
Namaste.

Rudeney

It's a common problem. The SRS wiring harness in the seat is a bit too tight. You can remove the seat back and the side plastic panels and manipulate it for some extra slack. You will need a proper scan tool (not a generic OBDII scanner) to reset the error - it won't clear on its own.

jwb007

Rudeney, Hope all is well. would you know/have any pics, that demonstrate how to remove the panel?
As a newbie and I am speaking for many in this forum. You're Sir, one/or the most knowledgeable, experience, helpful and involved participant at Mercedes forums. Its makes me wonder, who is the person behind the persona? Thank you for your continuous support and effort. Individuals like yourself, makes the difference. Like the old familiar Idiom"more like yourself, in every walks of life and this world would be a better place".

Rudeney

Removing se seat back panel is about as easy as it gets - there are two Torx bolts on the bottom edge than need to be remove, then it drops down and off. I don't have any photos of the SRS wiring, but it's not hard a tall to figure out - just trace them for the bag. If you need to remove the plastic covers over the seat hinge, there is are a few screws hold it;s tow halves together.

jwb007

thank you.

Patton001

This may be obvious but will that scanner work on a 2006 W209? In particular reset the SRS light?

Thanks

jwb007

HI, hope all is well. I didn't find any unplugged wire harness after removing the backs of both seat. Providing that's where they would be unplugged from?However; I noticed melted chocolate on a 'black' connector under the passenger seat. I removed all of the smeared chocolate and cleaned the hubs/ports with alcohol. I anxiously awaits on having the unit scanned.

Thanks

Rudeney

You may not find it unplugged. I think it just gets slightly loose where the harness plugs into the squib.

M-Rods

Congrats on the new purchase!!
Welcome to the fun of tracing electrical issues lol.

What do you thing of the Icarsoft scanner, I'm looking to get myself that for Christmas!