I have a 2003 Mercedes E500 that has developed an intermittent battery discharge problem. I have unplugged both of the front seat modules to insure that they are not the issue. But that did not solve it. So I have now unplugged fuse f41 which is the central gateway control unit. Is that the correct one to disconnect the audio gateway? With that fuse unplugged i am now getting a check engine light and a SRS warning light. So am a bit confused here to say the least. Also is there somewhere i can find a fuse chart for this car. Mine is missing and it shocks me the manual does not have this. Thanks for any help!!!! I have ordered an amp probe to use in helping me but it has not arrived yet.

Comments

Profile picture for user Boki

Hello! 

You need to check for parasitic drain. So, wait until your amp probe arrives.

When you have it, do the following:

- Remove the negative side battery cable from the negative battery terminal.

- Connect the black wire to the com input on a multimeter and the red wire to the 10A or 20A input on the multimeter. The meter needs to be able to read at least 2 or 3 amps for this test to work. Connecting the red wire to the mA input on the multimeter won't work and could damage the meter.

- Attach a multimeter (set the dial on the multimeter to measure Amps as per multimeters instructions) between the negative cable and the negative battery post. Wait a few seconds to several minutes for the car to go into sleep mode — i.e. when you make the contact with the ammeter, the car's computer systems "wake up." After a bit of time they will go back to "sleep."

- If the ammeter is reading over 25–50 milliamps, something is using too much battery power.

- ​​​​​​​Go to the fuse panel(s) and remove fuses, one at a time. Pull the main fuses (higher amp ratings) last. Perform the same steps on all relays found in the fuse panel. Sometimes relay contacts can fail to release, causing a drain. Be sure to observe the ammeter after pulling each fuse or relay.

- Watch for the ammeter to drop to acceptable drain. The fuse that reduces the drain is the draw. Consult the owners' manual or service manual to find what circuits are on that fuse.

- Check each device (circuit) on that fuse. Disconnect each lamp, heater, electrical device one at a time to find the drain.

 

Boki

Profile picture for user Phillip Jones

Thanks Boki!!!  Will do. The meter i bought is for checking low current draw so it should be plenty sensitive to do this. 

Profile picture for user Phillip Jones

ok so i attached my amp probe to the negative battery cable and it is reading a 1.5 to 2.5 amp draw. Every once in a while the draw may drop to only .4 amps. I have pulled every fuse and every relay in the car and none of them changes it. Any further ideas? I am at a loss other than putting a battery disconnect switch on it.

Profile picture for user Boki

Hi! 

Have you checked fuses in all three boxes (engine, trunk, dashboard)? 

Plain text

  • Allowed HTML tags: <a href hreflang> <em> <strong> <cite> <blockquote cite> <code> <ul type> <ol start type='1 A I'> <li> <dl> <dt> <dd> <h2 id='jump-*'> <h3 id> <h4 id> <h5 id> <h6 id>
  • No HTML tags allowed.
  • Lines and paragraphs break automatically.
  • Only images hosted on this site may be used in <img> tags.
The content of this field is kept private and will not be shown publicly.

Fuse boxes

4
JLew
2 months 2 weeks ago
Mercedes » S-Class » 2000-2006

Problem with automatic start

5
abchris
1 month 1 week ago
Audi » A3 S3 RS3 » 2015-____

Output Speed Sensor for 2011 Nissan Rogue

2
eantongiorgi@yahoo.com
4 months 2 weeks ago
Nissan » Rogue » 2008-2014

2010 Mercedes ML350 BlueTec fuel leak (Left tank)

0
tarheel3759
1 month ago
Mercedes » M-Class » 2006-2011

check liquid level

0
equintquant2
1 month ago
Mercedes » C-Class » 2001-2007

Mercedes Benz clk w208 supercharger

0
timcolledge
1 month ago
Mercedes » CLK-Class » 1998-2003

Dodge. Journey 2015

1
TennesseeRebel
1 month ago
Dodge » Journey » 2009-____

Is it my ignition switch?

0
lcserna0423
1 month ago
Dodge » Caravan » 2008-____

2009 Mercedes e350 rwd 80 k miles

2
lucapuca
1 month 1 week ago
Mercedes

2006 chrysler crossfire convertible top problem

2
daisyblemmons
1 month 1 week ago
Chrysler » Crossfire

Mercedes ML350 bluetec sputter misfire

1
Nmerc
1 month 1 week ago
Mercedes » M-Class » 2012-____

Fuel issue

1
Andrew Williams.90
1 month 1 week ago
Buick » LeSabre » 2000-2005

Brake system

2
tammyduran
1 month 1 week ago
BMW » Z4 » 2003-2008

Best Shocks for Grand Cherokee

2
JohnSmith75
1 month 1 week ago
Jeep » Grand Cherokee

W212 AMG seat swap

1
GPone
1 month 1 week ago
Mercedes

do you need to register new battery on 2006 z4???

1
jdgallo
1 month 1 week ago
BMW » Z4 » 2003-2008

Mercedes CLA 250

4
jc71
1 month 1 week ago
Mercedes

CHANGING DASHBOARD LANGUAGE

2
Master
1 month 1 week ago
Volvo » S40, V40

2004 f150 wont start

1
dldiggs2
1 month 1 week ago
Ford » F-Series » 2004-2008

2006 chrysler crossfire convertible top problem

1
daisyblemmons
1 month 1 week ago
Chrysler » Crossfire » 2004-2007

User has not asked any questions.

Disclaimer: Youcanic has made every effort to assure the accuracy of the information on this page. Neither Youcanic nor its affiliates assume responsibility for any loss or damage due to any errors, omissions, lack of information. You agree to hold Youcanic free from any liability arising out of the use of any information contained within. All pictures and references to trademarks and car names are for reference only and do not imply an association with the manufacturer. Consult your owner's manual or authorized factory manuals when performing repair procedures. By entering this site, you agree to our Terms & Conditions and Privacy Polity.