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Major Electrical Problems

5050 Views 4 Replies 4 Participants Last post by  PanamaTom
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
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Hi Tom
There's a sizeable slk group in Florida, so you may find somebody nearby who doesn't mind doing a scan for you.

How long have you had the car and how well do you know it's history?
I'm thinking flood damage and aftermarket electricals (alarm/stereo) which may be tapped into the wrong feed.

The only other thing I can think of is if any crash damage or rubbing has caused a short.

You've given MB knowlegable garages more than one go at this, how about an electrics specialist?

In the uk we can see previous owners details on the log book, if it's the same in the us maybe call them.
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form what I've read about knockoff star systems is that they're worth it for short term use, but as soon as an update comes out, they're no good anymore. i've looked into the price of a star system/computer and i know they're not cheap, by anyone's standard. IMO if you're willing to drop the money on a star system/computer, just take it to a dealership to have it diagnosed and repaired. doing so will keep the dealership liable for the fixes in case the gremlins may come back.

going off of what aver du said, see if someone local has a star scanner that may be able to help you read code and maybe diagnose.

being a technician myself i have a little experience with parasitic draws but unfortunately i can't help in this situation. if you happen to have it diagnosed let us know what you find out and we may be able to help point you in the right direction for a fix!
Not sure if this will help, but if you say you've removed everything and still getting the draw, I just came across quite a few posts about the instrument cluster causing battery drain on other Mercedes models, you might want to try removing the cluster and seeing if you still have the draw ??
Thanks guys for the quick replies

@Avel Du I purchased the car in August of '04 from a used car dealer. It looks like no major damage from underneath but there are places that were re-sprayed on the paint. Other than that I know nothing of the previous ownership. Might be time for a car facts report.

@SirClass I think that most of the upgrades would be to either fix glitches in the program or to add features for newer cars. I am hoping that it would not have to be upgraded. Some of the sites that sell them say NOT TO USE THE INTERNET so that it can't upgrade from MB because that will definitely shut it down. Like I said they charge $100 a pop to diagnose not to mention the labor rate to fix a problem. I just don't have that kind of money. I wouldn't have a MB if I had to pay to have it fixed.

@ curro101 I will see if I can disconnect the harness going to the cluster today.

Thanks for all your help
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