Does anyone have/know where to get a spec-sheet/diagram of the BCU (2003 D2)? My driver's side window is non-responsive.. wires seem fine, switch is good, motor is good, brand new regulator.. I'm getting a click coming from the BCU when the switch is activated up and down, but only when going from one to the other (once initially pressed to one direction, sequential presses in the same direction do not provide a click... relay maybe?). All other windows work fine, and I don't have any other BCU related issues, so this one has me scratching my head. Oh, and fuses are all good too (unless I'm missing one). So, I'd like to see if there are relays inside the actual BCU, or how things are laid out in there to help troubleshoot further. Connections look clean and solid too btw.

 

The RAVE manual has great information of the Valeo BCU specs and pin connections but it doesn't show the innards.
Here is the breakdown from Nanocom about the BCU... https://blackbox-solutions.com/help/SM023.html

 

Did you check the wiring to the window motor in the rubber boot between the body & the door? They can break inside the boot.

 

BODY CONTROL UNIT
86-3-22 DESCRIPTION AND OPERATION
Electric windows and sunroof
Three modes of operation are available:
l Driver cancel – the front windows, rear windows and sunroof will be disabled 44 seconds after the driver's door
is opened.
l All cancel – The front windows, rear windows and sunroof will be disabled 44 seconds after any door is opened.
l No cancel – the front windows, rear windows and sunroof will be disabled when the ignition is turned off.
The BCU will allow window and sunroof operation when the ignition key is in position II. The BCU provides a voltage
to the window control switches. When the switches are pressed, they provide a path to earth to complete the circuit
and initiate window operation. Window and sunroof operation is suspended when the ignition switch is in the crank
position.
For front window operation, the BCU checks the status of the following inputs:
l Ignition state.
l Driver's door open.
l Passenger or rear door open.
l Front right window down.
l Front right window up.
l Front left window down.
l Front left window up.
l Right window stall detect.
l Left window stall detect.
The front window motors are directly connected to the BCU by two wires. Each wire can be used as a feed or return,
dependent on the required direction for motor operation (open or close). The BCU provides the following outputs:
l Right window up.
l Right window down.
l Left window up.
l Left window down.
The electric front windows are enabled when the ignition switch is in position II and is disabled if the ignition switch is
moved to the crank position.
The BCU checks the status of the following inputs to determine when to provide the rear window enable and sunroof
enable output signals:
l Ignition state.
l Driver's door open.
l Passenger or rear door open.
The rear window enable and sunroof enable lines are on when the ignition switch is in position II, and are switched
off if the ignition switch is moved to the crank position.
The BCU monitors the circuit current draw when the windows are operating to detect the occurrence of a stall
condition. If the BCU determines that the window has stalled, it will cut the power supply to stop the operation of the
window motor. The BCU only starts to check for a stall condition after the window has been operating for 500 ms. This
delay period enables the initial current surge to pass and eliminates false detections of window stall. A stall condition
is activated when a nominal current value is exceeded for a period greater than 300 ms.
If the BCU detects that it has been operating the same window motor in one direction for more than 10 ± 0.2 seconds,
without the BCU detecting a stall condition or the control switch being released, it will automatically stop operation of
the window motor (timed out). Window operation can resume when the window switch is released and pressed again.
If the window was operating in one touch mode, the window operation will resume on the next press of the window
switch.
One touch mode automatically lowers the window to its fully open position, without the need for the window switch to
be kept pressed for the duration of the window travel. One touch mode is initialised if the window switch is pressed
for a period of less than 0.4 ± 0.2 second. One touch mode continues to lower the window until the BCU detects:
l A stall condition exists (window has reached bottom of travel).
l Window switch is repressed in either direction for more than 0.4 ± 0.2 second.
l The BCU has operated the motor for a period greater than 10 ± 0.2 seconds.
A timeout function is included which allows the windows and sunroofs to be operated for a period of 44 ± 1 seconds
after the ignition key has been removed from the ignition switch. The timeout function will be cancelled if the BCU
detects the following conditions:
l The driver's door has been closed after the ignition has been switched off.
l Any door open after the ignition is switched off.
The preconditions are programmed into the BCU dependent on market specification.
The BCU does not directly control rear window operation, but it can request the IDM to remove the power feed to the
rear windows. The IDM enables power supply to be provided to the rear lift relay in the passenger fuse box. When the
relay coil is energised the relay contacts close and power is applied to the rear window motor. If the window lift
isolation switch located in the centre console is latched out, the earth path from the LH and RH rear door window
switches is broken and operation of the rear window motors through the use of the rear window switches is prevented.
Rear window operation using the console switches is not affected by the isolation switch.
In the event of a communications link failure occurring while rear window enable is on, the relay remains on until the
ignition switch is turned to the off position.

 

Yeah. That was my first stop, hoping for an easy-ish fix. I admittedly, used the window more than I should have after the regulator failed... so I think I screwed up the BCU with the auto-stop feature reading erratic resistance? IDK though.

 

Yeah, I poured through all that in the Rave... was hoping I either missed something, or there was some new info out there in the world.

 

Did you verify the wires in the door? Are you getting 12v at the motor? The BCU is pretty robust. I've seen window motors burnt to a crisp inside and the BCU was still sending it 12v.

 

No power being sent (either direction). One side-note that might be worth mentioning though... The new motor does not move at all by hand.. Only when powered. Is that normal? In my head that makes sense to prevent the window sliding down when the voltage is cut. But if that's not the case, perhaps the bcu is sensing the resistance and thinking it's closed, and cutting the voltage? The motor I replaced was pretty well shot, and the gears were stripped. I didn't think to test the movement before tossing it. But, as I'm typing this, I realize that when testing the wires, there wouldn't be any load involved (as the motor wasn't in line).

 

the d2 electrical library gives much more detail about the actual pins of the bcu and the wire colours involved. that might have the info you're looking for.