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2000 e430
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20 Posts
Discussion Starter #1
My 2000 e430 rear windows do not work. I bought the car in this condition. I started messing with the driver side window and it fell into the door. I had the unit including motor replaced. This fixed the window now locked into closed position but not the power. Light tested leads in the door and nothing. I then took center console apart and completely took apart the windows control unit and cleaned it. Still nothing. Light tested switches on board. Nothing. I went to junk yard and got 2 of these units and plugged them in and still nothing. Only the front windows work in all situations. Could all 3 units have been faulty? A new piece is pricey.
 

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Premium Member
1998 E320 base sedan @ 160kmiles
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6,678 Posts
Try resetting the system by disconnecting the car battery for 15 minutes or so (with the keys in your pocket, knowing radio activation code, and knowing how to synch the windows, seat and sunroof).

The car window modules talk to the controller module (LCP, lower console module, where the windows buttons are) through the SAM module. Kind of communications network. If a fault is detected the faulty modules are disabled so they do not disturb the comm network. Resetting,
sometimes restores the connections.

Of course, make sure that the rear door control modules are powered by their respective fuses.

Also try the window switch on the rear door. It has a direct connection to the motor control (unlike the center console buttons).
 

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2000 e430
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20 Posts
Discussion Starter #3
I checked rear switches all 3 times I switched out a control board. Should I have reset car each time I did this? Also when I bought the car it was dead. I replaced the battery after 2 years of not running and she fired right up. No rear windows though. Should I still try to reset and sink everything?
 

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Premium Member
1998 E320 base sedan @ 160kmiles
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6,678 Posts
Check fuses first. For the

-Driver side rear window: Fuse 18 under the hood (driver side fuse panel)
-Passenger side window: Fuse 2 Under the rear seat fuse panel next to the battery.

20 amp each.

How did you check the switches ? They are voltage coded, meaning they have resistors inside, so when you press up/down and second stage up/down for synching) you get different resistor values for the controller to decode.

Also make sure the child safety lock switch is off (center console).

If you have no power coming to the modules there is no chance they will work
 

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2000 e430
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Discussion Starter #5
I will go and recheck fuses. Had a hard time finding them at first. I checked the switches on board with a light tester. I first started with the front switches since I knew they worked and found 2 spots where the light came on when the switch was activated. I then used this technique on the rear switches and there is nothing. This all done on the center console.
 

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1997 E300D
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508 Posts
since you are new to the car I want to double check that you have the child safety switch on the consol in the position that enables the rear windows? It is a small button between the driver side window switches. If the picture of a child is visible, the windows in back are disabled. Flip the switch. The window that fell down likely has a broken regulator. The rear regulators are failure prone.
 

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2000 e430
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Discussion Starter #9
The child lock is off. We took apart the back driver door to swap out the track and motor to at least keep the window up. Hooked it all up and nothing. I swapped out the control board from my 2000 e320 that worked and tried it on the e430 and still nothing. Not the fuses. Not the reset thing. Not the motors. Just 0 power. swapping out the board and all of the same stuff that worked still worked.
 

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1998 E320 base sedan @ 160kmiles
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6,678 Posts
You check the fuses but did you check the power on both sides of the fuses in the front (fuse 18) and rear (fuse fuse 2) panel ? Fuses may be OK but there may be problems with the fuse holder or wiring to fuse holder.

Also check power at the rear door control module connector (between red/green wire and the brown wire) You should have power there all times, if not, you have a wiring issue.
 

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2000 E430
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52 Posts
You check the fuses but did you check the power on both sides of the fuses in the front (fuse 18) and rear (fuse fuse 2) panel ? Fuses may be OK but there may be problems with the fuse holder or wiring to fuse holder.

Also check power at the rear door control module connector (between red/green wire and the brown wire) You should have power there all times, if not, you have a wiring issue.
With all fuses checked good, I have no voltage at the right rear door control module connector (red/green to brown wires). All other windows are operating normally. Can you suggest the next step to track down the cause of power cut off to the door module?
 

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1998 E320 base sedan @ 160kmiles
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6,678 Posts
OK,
1) Check that you have 12V on both sides of fuse #2 (under the rear seat fuse panel) with respect to chassis. This will indicate that you have power going into the fuse, and going out.
2) Have a look at the attached diagram. The power (12V) is red/yellow, and 2.5 mm thick cable (pin 8 on the DCM). The ground is a 2.5 mm thick brown wire going to pin 3. If you have no voltage between these two pins as you reported:

2.1 Measure the voltage between pin 8 (red/yellow wire) and metalwork of the car (the front seat metal track for example). If you measure 12V, then you have a disconnect with the ground lead (brown). You can confirm it by measuring resistance between the brown lead and the metal track of the front passenger seat meat. It should read close to zero Ohms.

2.2 If you cannot read 12V between the red/yellow wire and the track of the seat, then you have a problem with the 12V supply wire.

If you detect a disconnect in either ground, or 12V supply line, it is likely at the wiring harness where the hinge is. There is a termina,l X35/4, as shown in the diagram which is probably in the door sill.
 

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2000 E430
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Power tests good on both sides of fuse #2 under rear seat. Ground wire at DCM connector tests good, so that points at the 12v supply line as the culprit. Looks like I will need to dig out the buried harness at the door hinge/closure area. Oy. Maybe I just live with a right rear window that stays up at all times... :)
 

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2000 E430
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One more new symptom that may be relevant: seeming to have stopped working at about the same time as the passenger side rear window is the passenger side rear view mirror back up function. Not sure the right name for this; this is when the mirror rotates downward to help view the curb when placing the transmission in reverse. Any ideas?
 

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1998 E320 base sedan @ 160kmiles
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You need to make sure that the mirror control switch is set to select the passenger side mirror, and left there. If it points to the driver's side, the reverse mirror dip will not be functional.
 

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1998 E320 base sedan @ 160kmiles
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6,678 Posts
Do your back up lights work? The switch for the reverse lights is in the shifter. If the gear is put to R, the same circuit signals to SAM / LCP (the module where the window and mirror switches are) to tell the door control module at the passenger side to dip the passenger side mirror. This is an unrelated problem with the rear window DCM not getting power.
 

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2000 E430
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52 Posts
Thanks for confirming that these issues are unrelated. I will look into the mirror/reverse/back up light issue when I get home in a week.
 

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W210 Moderator
99 E320
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5,106 Posts
It wouldn't hurt to remove the mirror cover and clean out the hornets nest,
leaves, etc...and manipulate the mirror to full travel all around, then try the
switch control again.
 
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