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Wiring damage on my CL63 (M156) – seeking advice on repair options
Hi everyone,
I'm currently working on my 2008 CL63 AMG with the M156 engine and have encountered a common issue: some of the wiring, particularly around the fuel injector connectors, is brittle and has exposed insulation. I’ve already removed the intake manifold to gain better access to the harness.
At this point, I'm evaluating the next steps and would appreciate input on a few specific questions:
Are there differences in the engine harness between LHD and RHD cars (e.g., routing, length, connector orientation)?
Is the harness from other M156 models like the C63, E63, or S63 compatible with the CL63? I know the ECU is positioned differently in some of those models, so I'm wondering if the harness layout differs as well.
I can’t remove the A/C compressor at the moment, which is blocking access to the oil temperature sensor. Would it make sense to restore only the top half of the harness up to the ECU connectors, or is it critical to remove the full harness and replace or repair it end-to-end? Is it even possible to disconnect the oil sensor without taking off the compressor?
Any thoughts or experience with this would be much appreciated. Thanks in advance!
Thanks, but I know about them and my car has even been on their service. Their repair kit will not help in my case, the wiring is more damaged. When they had the car in for service, they said their repair kit wouldn't help in my case.
Last edited by TheDictator; May 22, 2025 at 01:52 PM.
I'm currently working on my 2008 CL63 AMG with the M156 engine and have encountered a common issue: some of the wiring, particularly around the fuel injector connectors, is brittle and has exposed insulation. I’ve already removed the intake manifold to gain better access to the harness.
At this point, I'm evaluating the next steps and would appreciate input on a few specific questions:
Are there differences in the engine harness between LHD and RHD cars (e.g., routing, length, connector orientation)?
Yes, they are!
Is the harness from other M156 models like the C63, E63, or S63 compatible with the CL63? I know the ECU is positioned differently in some of those models, so I'm wondering if the harness layout differs as well.
No, they are not!
I can’t remove the A/C compressor at the moment, which is blocking access to the oil temperature sensor. Would it make sense to restore only the top half of the harness up to the ECU connectors, or is it critical to remove the full harness and replace or repair it end-to-end? Is it even possible to disconnect the oil sensor without taking off the compressor?
Have the entire harness redone end-to-end!
Yes, it should be possible, but honestly, when I was replacing the harness on my E63, I also replaced the starter, alternator and power steering pump, which made things much easier once those came out of the car. I also removed the supercharger, because a part of the harness runs under the Intake Manifold.
Any thoughts or experience with this would be much appreciated. Thanks in advance!
I used MKB-TEC in German to rebuild the M156 wire harness. The repaired harness looked brand new and works great! They are also using better-quality wire insulation, so the stripping issue is unlikely to return anytime soon. Here are pics of the rebuilt wire harness.
You can visit them over at: www.mkb-tec.com
I used MKB-TEC in German to rebuild the M156 wire harness. The repaired harness looked brand new and works great! They are also using better-quality wire insulation, so the stripping issue is unlikely to return anytime soon. Here are pics of the rebuilt wire harness.
You can visit them over at: www.mkb-tec.com
Good luck!
Thank you very much for your reply. I also removed the intake manifold to get to the wiring that runs under it, but I still haven't solved the problem with the wiring that goes under the engine on the driver's side. I have already ordered two more used wiring harnesses to either replace or restore all three.
Did you remove the air conditioner compressor to access the oil and coolant sensors?
On my CL, the hydraulic suspension and power steering fluid reservoirs are also located on the driver's side. I would really prefer not to remove them, as they are in perfect working order.
I know about MKB TEC, the price is now 2100, although it used to be 2500, which is very expensive for this kind of work. And they raised the price as soon as the wiring became unavailable for order. It seems a little unfair and like they are just taking advantage of the situation. Before that, the price was 1500 or 1300, I don't remember exactly.
I was also changing the power steering pump, so I moved the AC compressor out of the way (to get to the power steering pump) but didn't remove it from the car or disconnect any of the hoses (didn't want to have to gas it back up when I was done). I also changed the engine mounts, so I removed the exhaust pipes beyond the exhaust manifold, which made it easier to remove the harness from the car.
That's interesting. On the E63, the tank is normally located just in front of the IM. Because my car is supercharged, my power steering tank is on the Pax side, just behind the headlight. It seems that there are a few differences between models, so you may need to spend some time tracing where the harness runs and then determine what needs to be removed to give you the best access without breaking anything. The main issue is getting enough access to disconnect the various plugs from the sensors and components. You really don't want to break any of those plugs unless you are okay with finding replacements online.
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Wiring damage on my CL63 (M156) – seeking advice on repair options
