Crucian

Hey guys just joined today but have been browsing this site for months! I bout my 05 e500 last year and this problem began around Nov last year first it would be a little hiccup in the morning but now it only stays charge for about 2hrs I have to take of the terminal if I plan to not use it for more than 2hrs I live in the Virgin Islands st croix and we do not have any certified mb shops so everyone I go to is Indy. I am looking for a wiring diagram that can show my electrician because he says if he sees that he will find the root of the problem! I have taken it to some Indy shops and keep getting different responses one says the battery control module but he was not definite the other says a ground wire and that I need an electrician! So my questions are where do I find a wiring diagram for the whole car that I can print out to take to my electrician and what could possibly be the problem?

biker349

i've read that sometimes the seats can cause a drain. disconnect the seat memory switches and see what happens.

mohd.awaly

Well mate its an awful thing but you should start pulling out some fuses ... go to the fuse box take out some fuses ( radio . Seats . Mirrors . Navigation ... etc ) .. not all fuses , maybe 5 at a time and wait for 2 hours and see what happens ... this way you will be able to narrow it down ...

Dnt know where you can get diagrams for the whole car ...

whoover

The diagrams wouldn't help. It's really hard to diagnose these things without the proper equipment, and it's usually something "odd." To understand why, you have to know that all the controls and switches in the car just put computer-like signals on a bus, which are picked up by two units called SAMs (signal acquisition/activation modules), which in turn do the actual switching of the electrical consumer. This minimizes the amount of heavy copper wire in the car, and replaces most of the "wiring" with fiber or thin copper.

There are also several networks, called CANs, which those SAMs talk to. One CAN shuts down when the car is turned off, after giving you time to finish moving seat around, etc. If it doesn't shut down, a lot of devices stay powered up that should be off, drawing a lot of current. A common problem is a seat controller that generates electrical noise, keeping the CAN from going to sleep. The controller module isn't drawing the current, but it's keeping a vast network from powering down, which draws the current.

Here are a couple of starter references:
http://www.mercedestechstore.com/pdf...2010-28-02.pdf

http://www.continentalimports.com/ser_ic030538.html

This is a common scenario, but the point is that you really need to understand these SAMs and CANs and know how to diagnose them if you're going to fix this kind of a problem. It's not something an electrician can do.

Boss man

Hey saw the responses changed my alternator changed my bcm now I am thinking about getting an mb star c3 do you think that will show the power drain or what should I start trying to replace and if I pull the 5 fuses why would I have to wait 5 hours?

MagCL

First off, make sure your battery is good and holds the charge. If it is good, you need to do a parasitic drain test with a meter that can measure DC current up to 10 AMPS. There are a bunch of youtube videos and sites on the web that will show you how to do it. Just remember to connect the meter and wait at least 30 minutes for the car to go to sleep before you start pulling fuses.