How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask MB Paul Your Own Question
MB Paul
MB Paul, Mercedes Technician
Category: Mercedes
Satisfied Customers: 3567
Experience:  Qualified Mercedes Benz Diagnostic Technician - 20+ years experience - Workshop Foreman for Mercedes
Type Your Mercedes Question Here...
MB Paul is online now
A new question is answered every 9 seconds

Main battery goes dead. I bought E500 from factory in 2004.

Customer Question

Main battery goes dead. I bought E500 from factory in 2004. Has been flawless until the main battery began dying overnight. Have tried the pulling fuses one by one and each time I think it is solved, I am proved wrong. Both batteries have been replaced, more than once. I narrowed it down to the Audio Gateway, but is obviously false as it still goes dead without warning. This has been happening for over 4 years now.
JA: Did you test the battery with a voltmeter? And have you ever changed one before?
Customer: I will donate my left nut if you can solve this...
JA: What year is your E500?
Customer: I am an engineer and have been taking things including cars apart since about 14. Yes I have done pretty much everything. I am 62 and have been around the block a few times.
JA: Are you fixing your E500 yourself? What have you tried so far?
Customer: As I said earlier, I have tried the removing fuses to isolate the problem, but it is still elusive.
JA: Anything else you want the mechanic to know before I connect you?
Customer: Only that I have replaced both batteries more than once...they are not the problem.
Submitted: 9 months ago.
Category: Mercedes
Customer: replied 9 months ago.
We have you bastards now. You will be unable to get out of this one.
Expert:  Lou P. master tech replied 9 months ago.

Hello, my name is***** and i will do my best to assist you.I am going over your story now and will reply back soon with some info,thanks!

Expert:  Lou P. master tech replied 9 months ago.

the audio gateway is the most common draw in the E class model, the quiescent draw test on a mercedes can be tedious, can you tell me how you are performing the draw test?