Battery drain seat control module question
Thread Starter
Junior Member
Joined: Jun 2016
Posts: 50
Likes: 2
From: St. Louis MO
07 E63
Battery drain seat control module question
I recently purchased an 02 C32 and it appears to have the battery drain issue. After looking on this forum, I disconnected both driver & pass seat control modules and no longer a dead battery in the morning. So, if I leave one seat unplugged and plug the other in (then retest battery voltage), would this give me an idea which module is bad? Do I have to replace both regardless? Somewhere on this forum I read you had to replace both even if only one is bad (not sure that's true). The Mazda dealer I purchased from said they repaired the passenger seat (seat didn't move). Guess that doesn't necessarily mean they replaced the module though.
Any opinions? At $150 each I don't want to replace both if one is still good.
Thanks!
Any opinions? At $150 each I don't want to replace both if one is still good.
Thanks!
Super Member
Joined: Jul 2014
Posts: 992
Likes: 245
From: Tucson, AZ
'20 X5 M50i; '17 Ram 3500; Golf Cart; Bikes; Scooters
Here are the instructions for disabling the seat module with key off that I found in the forums. Have not done this (yet), so test your power supply to these wires before cutting anything.
Instructions:
This is to make the seat only operate when the key is on, not when off.
NOTE: This will work on all W203, BUT you may have different colors. Please check the voltage before splicing.
Tools you need:
(2) - Wire Splicers (or soldering kit)
Electrical Tape
Wire Cutter
1) Look under your seat and find the connector with the 3 wires.
(BROWN),(RED WITH GREEN STRIPE),(BLACK WITH WHITE STRIPE) and disconnect it.
The Brown Is Ground
The Red Is +Positive Constant 12v
The Black is +Positive only when key is turned on position 12v
2) Remove some of the electrical tape on the wire loom.
3) Cut the Red wire and Splice it with the Black wire.
4) !!! Make sure you tape off the RED 12v coming in from the connector !!!
5) Wrap everything up with electrical tape and you’re done. Now test. Seat should only operate when the key is on, not when off.
Instructions:
This is to make the seat only operate when the key is on, not when off.
NOTE: This will work on all W203, BUT you may have different colors. Please check the voltage before splicing.
Tools you need:
(2) - Wire Splicers (or soldering kit)
Electrical Tape
Wire Cutter
1) Look under your seat and find the connector with the 3 wires.
(BROWN),(RED WITH GREEN STRIPE),(BLACK WITH WHITE STRIPE) and disconnect it.
The Brown Is Ground
The Red Is +Positive Constant 12v
The Black is +Positive only when key is turned on position 12v
2) Remove some of the electrical tape on the wire loom.
3) Cut the Red wire and Splice it with the Black wire.
4) !!! Make sure you tape off the RED 12v coming in from the connector !!!
5) Wrap everything up with electrical tape and you’re done. Now test. Seat should only operate when the key is on, not when off.
Last edited by kbob999; Jul 13, 2016 at 12:35 PM.
Super Member
Joined: Aug 2014
Posts: 636
Likes: 19
C32 amg
Here are the instructions for disabling the seat module with key off that I found in the forums. Have not done this (yet), so test your power supply to these wires before cutting anything.
Instructions:
This is to make the seat only operate when the key is on, not when off.
NOTE: This will work on all W203, BUT you may have different colors. Please check the voltage before splicing.
Tools you need:
(2) - Wire Splicers (or soldering kit)
Electrical Tape
Wire Cutter
1) Look under your seat and find the connector with the 3 wires.
(BROWN),(RED WITH GREEN STRIPE),(BLACK WITH WHITE STRIPE) and disconnect it.
The Brown Is Ground
The Red Is +Positive Constant 12v
The Black is +Positive only when key is turned on position 12v
2) Remove some of the electrical tape on the wire loom.
3) Cut the Red wire and Splice it with the Black wire.
4) !!! Make sure you tape off the RED 12v coming in from the connector !!!
5) Wrap everything up with electrical tape and you’re done. Now test. Seat should only operate when the key is on, not when off.
Instructions:
This is to make the seat only operate when the key is on, not when off.
NOTE: This will work on all W203, BUT you may have different colors. Please check the voltage before splicing.
Tools you need:
(2) - Wire Splicers (or soldering kit)
Electrical Tape
Wire Cutter
1) Look under your seat and find the connector with the 3 wires.
(BROWN),(RED WITH GREEN STRIPE),(BLACK WITH WHITE STRIPE) and disconnect it.
The Brown Is Ground
The Red Is +Positive Constant 12v
The Black is +Positive only when key is turned on position 12v
2) Remove some of the electrical tape on the wire loom.
3) Cut the Red wire and Splice it with the Black wire.
4) !!! Make sure you tape off the RED 12v coming in from the connector !!!
5) Wrap everything up with electrical tape and you’re done. Now test. Seat should only operate when the key is on, not when off.
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Thread Starter
Junior Member
Joined: Jun 2016
Posts: 50
Likes: 2
From: St. Louis MO
07 E63
Sounds like others have done this mod with success, so I will attempt it this weekend. I have no problem with it only working when I turn the key. Does anyone have a picture? Seems simple but don't want to screw it up.
Thanks!
Thanks!
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Member
Joined: Feb 2014
Posts: 134
Likes: 10
From: New Hampshire
C 32 AMG & FG2 Civic Si
yeap i've unplugged one at a time and left it for a few days to figure out which seat control module was toast. turned out to be my drivers side. i replaced it but left immediately for a couple of months and have not been back yet to test the replacement.
in any case, i highly recommend getting the part through fcp euro. they'll send you the new, oem part literally below mercedes's cost. i have a friend who works at a merc dealership and showed me cost info, so that's how i figured that out.
good luck!
in any case, i highly recommend getting the part through fcp euro. they'll send you the new, oem part literally below mercedes's cost. i have a friend who works at a merc dealership and showed me cost info, so that's how i figured that out.
good luck!
Newbie
Joined: Dec 2016
Posts: 3
Likes: 0
C320
Please provide pictures. I'm a noob
Please provide pictures on where to cut and splice, I'm new to this and I didn't understand how to do it properly. Thank you
Here are the instructions for disabling the seat module with key off that I found in the forums. Have not done this (yet), so test your power supply to these wires before cutting anything.
Instructions:
This is to make the seat only operate when the key is on, not when off.
NOTE: This will work on all W203, BUT you may have different colors. Please check the voltage before splicing.
Tools you need:
(2) - Wire Splicers (or soldering kit)
Electrical Tape
Wire Cutter
1) Look under your seat and find the connector with the 3 wires.
(BROWN),(RED WITH GREEN STRIPE),(BLACK WITH WHITE STRIPE) and disconnect it.
The Brown Is Ground
The Red Is +Positive Constant 12v
The Black is +Positive only when key is turned on position 12v
2) Remove some of the electrical tape on the wire loom.
3) Cut the Red wire and Splice it with the Black wire.
4) !!! Make sure you tape off the RED 12v coming in from the connector !!!
5) Wrap everything up with electrical tape and you’re done. Now test. Seat should only operate when the key is on, not when off.
Instructions:
This is to make the seat only operate when the key is on, not when off.
NOTE: This will work on all W203, BUT you may have different colors. Please check the voltage before splicing.
Tools you need:
(2) - Wire Splicers (or soldering kit)
Electrical Tape
Wire Cutter
1) Look under your seat and find the connector with the 3 wires.
(BROWN),(RED WITH GREEN STRIPE),(BLACK WITH WHITE STRIPE) and disconnect it.
The Brown Is Ground
The Red Is +Positive Constant 12v
The Black is +Positive only when key is turned on position 12v
2) Remove some of the electrical tape on the wire loom.
3) Cut the Red wire and Splice it with the Black wire.
4) !!! Make sure you tape off the RED 12v coming in from the connector !!!
5) Wrap everything up with electrical tape and you’re done. Now test. Seat should only operate when the key is on, not when off.
