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Major Electrical Problems

Old 02-01-2016, 12:59 PM
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Default Major Electrical Problems

Let me start by saying that some of the problems have been posted in other threads but mine is different. I am sorry for the long post but I think that it is important for you to have the background.

I have a 2003 SLK 230 with about 130k miles.

When I purchased it everything was fine. After about 3 moths I had a problem with the ESP/BAS light came on and went into limp mode. Long story short I scanned the car with a generic OBDII scanner and proceeded to replaced the LR wheel sensor, the conductor plate and transmission electrical plug also the transmission had 0 transmission fluid showing on the new stick I purchased, so I filled it with fluid (MB Rated).

I brought it to an independent MB certified shop. They removed the codes and everything was fine for an hour. Then the light came on I brought it back and they re scanned it and no codes came up so they turned the wheel back and forth and the lights went out.

Great for about 2 months then the check engine and ABS ESP/ BAS lights came on again. I scanned it with a generic code scanner and got a couple of codes that didn't make sense implausible readings. I took it back to the indi and had it re scanned. This time they said the battery was causing the problems and sold me a new battery. Everything worked as it should for about 6 months. Then everything started to happen.

The ABS ESP/ BAS lights came on again but not in limp mode lasted for a while then went out.
The Roof Went down but would not go back up so I had to put it up manually. then I tried to work the switch to get the rear windows up and got the quick flashing light ( Codes in the retractable roof system). I finally was able to get the windows to close.
The ABS ESP/ BAS lights came on again and are staying on
The latest thing is that the battery went dead, I disconnected the negative cable and charged it. I then put an ammeter on the negative side between the battery and cable and I get .3 to .4 flow. So I know something is not shutting down. I tried to connect it again using a separate battery so the car thinks that the battery is connected then took off the extra battery while the ampmeter is still connected. I then started to unplug all of the fuses, then unplug all of the relays and computer plugs, still have the draw. I purchased another scanner that would read MB specific codes (Icarsoft MBII scanner), went through all of the systems and cleared all of the codes. The car now runs great but the ESP/ BAS light is on. THIS SCANNER DOES NOT DO THE ROOF and a couple of other systems. I sent the Icarsoft MBII scanner back for a refund so I can invest in a Star system.

My problem now is if I leave the battery connected it goes dead over night and if I unplug the negative I'm doing a hard boot on all of the computers and all of the ABS ESP/ BAS lights come on.

Even with the lights on the car runs great and on my basic OBD scanner there are no codes. I read on some forum that there is a MB Star system (from China) that the forum guys said worked great but I didn't link the page so it is in the Inter-Web black hole.

Now for my questions:

What should the amperage draw be with the key off and all of the systems shut down?
How can I find where the draw is coming from?
Has anyone used that knockoff star system and Is it worth the investment? It sells for around $ 400 dollars.
The dealer charges $100 every time he hooks it up.
AGAIN sorry for the long post. I would appreciate any input that you have.

Thanks in advance
Panama Tom
Old 02-02-2016, 06:32 PM
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Does the cruise control work when the esp lights are on?
Old 02-03-2016, 10:14 AM
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I checked all of the systems yesterday after I plugged in all of the harnesses. this is what did NOT work: directional signals, Lock switch, cruse control, Emergency flasher, Top Up/or down no light at all and probably others I forgot to test.

The voltage drop last night went from 12.57 to 12.22 in about 14 hours. O am thinking that there may be a connector or two that are not clean so I am going to unplug them all again and spray with electrical cleaner and coat with dialectic grease and see what happens.
Old 02-05-2016, 04:15 AM
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the 170 820 09 26 module controls most of what you said didn't work. on my sl, I disconnected my battery ground and touched the terminal and it would have a pretty good spark indicating a draw. I started with the fuses like you did and pulled one at a time then to unplugging everything starting with the easiest to get at. When I unplugged the power antenna just a very slight spark, meaning that was my issue. A meter would work too, this was easier for me. This worked better than taking it to several servicers that could never find the problem, but did a lot of expensive part guessing and labor for nothing.

Last edited by brookings; 02-19-2016 at 02:34 AM.
Old 02-15-2016, 05:55 PM
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I have finished cleaning all of the components I could find. I did find that the computer in the trunk was wet, however, When I took it in and looked at it closely everything looks dry inside ( newer upside down ) just a wet trunk floor.

When I finished all of the computers I found that in the box by the Battery the 3 computers had the wires all crossed so the cover would not go back down. While playing with the wiring I noticed that the one closest to the battery was going in but not seating correctly. I finally got all of them in correctly and everything works.

Except for the bas/esp light and the Vario top. The top button when pushed toward the rear now Blinks and when pushed forward The pump goes on and it sounds like something in the trunk is moving, this happens for a second or two then the light goes out.

Now I just have to decide what scanner to pick up. With all of variables that you read about I believe there are 3 types ( brands) that will give the Mercedes codes. I just have to pick one and try.

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