UKSkydiver
New Member
Hey all
Recently picked up a CLC180 coupe. [EDIT: it looks like this model is actually a CL203, not W203 - apols] I have an issue which I'd like your collective knowledge on please. I have done a search. And sorry for the length of the post, I like to provide detail.
I bought this vehicle a couple of weeks ago. Week one, no issues.
On Friday, end of week one, I have an auto-locksmith cut and code me a new key as the vehicle only came with one. He had some issues coding the keys back to my original ignition module (EIS), so to get me going, he puts in a 'spare' temporary EIS while he orders a replacement . This may be relevant to the story.
On Saturday, I did a couple of long runs, but on Monday I woke to a dead battery. One of the things I eventually noticed was a permanently on ambient light (the one underneath the rear view mirror) This amber light stays on no matter what. It does not turn off when I take the key from the ignition and it does not turn off "some time later". There are no options on the on board computer to affect the behaviour of this light. All of the other internal lights appear to work correctly and turn off as expected when the doors close / vehicle is locked. Incidentally, my wife has an SLK and her ambient light turns off as soon as the ignition is switched off.
So the locksmith comes back with the new EIS and I tell him this story. I ask him to put in the original one back in to see if the ambient light goes off. It does not. He puts in the new replacement EIS. The ambient light still remains illuminated. He goes on his way.
So I'm now into parasitic draw mode. At steady state, after all the door are closed and we wait a while, the draw is about 0.17 amps. I start pulling fuses and eventually it drops when I remove fuse 9 from the fuse box in the boot. This fuse is, maybe not surprisingly, for the overhead control panel (OCP) control box. When I take this out, the ambient light goes off and the draw drops to about 0.08amps. I read that 0.05-0.08amps is acceptable - so it's at the higher end....
In the meantime I speak to a MB dealer about this and they suggest unplugging the ambient light from the OCP. I managed to remove a couple of plugs, one for the ambient light and another which I'm not sure what it's for, but reduced the draw a little further.
These are the two that I've disconnected. The white one on the right is the one to the ambient light in the mirror.
Whilst I was in there I noted the voltages to the supply plug to the OCP here:
This morning, where the vehicle would be completely dead and not respond to the remote unlock, I have been able to successfully unlock and start it up - so I've removed the problem, but not fixed the root cause.
So my questions are thus:
- Do we think that the draw causing the flat battery was likely not present during week one, given that I had no power issues up until then?
- Is it possible that the unknown temporary EIS caused an issue with the electrics somewhere?
- Do we think that the OCP is faulty?
- I've read about a SAM that might also be in the mix. Do we think that a SAM might be faulty?
- Can anyone assist in telling me which SAM it might be as I believe there could be a few.
- Can anyone give advice how to test the SAM (I should say that I don't have access to any STAR / Autel type devices)
- Plus anything else that might be pertinent that I've missed.
Many thanks in advance
Cheers, Phil
Recently picked up a CLC180 coupe. [EDIT: it looks like this model is actually a CL203, not W203 - apols] I have an issue which I'd like your collective knowledge on please. I have done a search. And sorry for the length of the post, I like to provide detail.
I bought this vehicle a couple of weeks ago. Week one, no issues.
On Friday, end of week one, I have an auto-locksmith cut and code me a new key as the vehicle only came with one. He had some issues coding the keys back to my original ignition module (EIS), so to get me going, he puts in a 'spare' temporary EIS while he orders a replacement . This may be relevant to the story.
On Saturday, I did a couple of long runs, but on Monday I woke to a dead battery. One of the things I eventually noticed was a permanently on ambient light (the one underneath the rear view mirror) This amber light stays on no matter what. It does not turn off when I take the key from the ignition and it does not turn off "some time later". There are no options on the on board computer to affect the behaviour of this light. All of the other internal lights appear to work correctly and turn off as expected when the doors close / vehicle is locked. Incidentally, my wife has an SLK and her ambient light turns off as soon as the ignition is switched off.
So the locksmith comes back with the new EIS and I tell him this story. I ask him to put in the original one back in to see if the ambient light goes off. It does not. He puts in the new replacement EIS. The ambient light still remains illuminated. He goes on his way.
So I'm now into parasitic draw mode. At steady state, after all the door are closed and we wait a while, the draw is about 0.17 amps. I start pulling fuses and eventually it drops when I remove fuse 9 from the fuse box in the boot. This fuse is, maybe not surprisingly, for the overhead control panel (OCP) control box. When I take this out, the ambient light goes off and the draw drops to about 0.08amps. I read that 0.05-0.08amps is acceptable - so it's at the higher end....
In the meantime I speak to a MB dealer about this and they suggest unplugging the ambient light from the OCP. I managed to remove a couple of plugs, one for the ambient light and another which I'm not sure what it's for, but reduced the draw a little further.
These are the two that I've disconnected. The white one on the right is the one to the ambient light in the mirror.
Whilst I was in there I noted the voltages to the supply plug to the OCP here:
This morning, where the vehicle would be completely dead and not respond to the remote unlock, I have been able to successfully unlock and start it up - so I've removed the problem, but not fixed the root cause.
So my questions are thus:
- Do we think that the draw causing the flat battery was likely not present during week one, given that I had no power issues up until then?
- Is it possible that the unknown temporary EIS caused an issue with the electrics somewhere?
- Do we think that the OCP is faulty?
- I've read about a SAM that might also be in the mix. Do we think that a SAM might be faulty?
- Can anyone assist in telling me which SAM it might be as I believe there could be a few.
- Can anyone give advice how to test the SAM (I should say that I don't have access to any STAR / Autel type devices)
- Plus anything else that might be pertinent that I've missed.
Many thanks in advance
Cheers, Phil
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