With the 664 plug disconnected from the BCU

If i ground and power the silver blue and sliver pink, the right front window goes up and down. Green zip tie wires

If i do the same to the slate red and green black, looks like 1 and 4, nothing happens. The BCU clicks, but the Lefthand windows do not move.


From RAVE:
Front left window up
The left window switch up contact is connected to pin C0660-18 on the BCU by a BS wire.
When the switch is set to the up position an internal supply from the BCU flows along the BS
wire through the contacts of the switch and to earth via earth header C0552 on a B wire.
The BCU internal logic monitors the current flow from pin C0660-18 and uses this input as
an up signal. The BCU routes power from the permanent feed from pin C0664-7 to pin
C0664-4. From pin C0664-4, the power flows to connector interface C0463-6/C0744-6 on
an SB wire, and from the connector interface to the LH front window motor on a SU wire.
The motor is energised and drives the window mechanism towards the up position.
The front left window motor is earthed via an SK wire to connector interface C0744-7/C0463-
7, and an SR wire from the connector interface to pin C0664-1 on the BCU. The BCU
completes the earth via pin C0664-5 on a B wire to earth header C0018 LHD/C0017 RHD.
Front left window down
The left window switch down contact is connected to pin C0662-1 on the BCU by a BR wire.
When the switch is set to the down position an internal supply from the BCU flows along the
BR wire through the contacts of the switch and to earth via earth header C0552 on a B wire.
The BCU internal logic monitors the current flow from pin C0662-1 and uses this input as a
down signal. The BCU routes power from the permanent feed from pin C0664-7 to pin
C0664-1. From pin C0664-1, the power flows to connector interface C0463-7/C0744-7 on
an SR wire, and from the connector interface to the LH front window motor on a SK wire.
The motor is energised and drives the window mechanism towards the down position.
The front left window motor is earthed via an SU wire to connector interface C0744-6/C0463-
6, and an SB wire from the connector interface to pin C0664-4 on the BCU. The BCU
completes the earth via pin C0664-5 on a B wire to earth header C0018 LHD/C0017 RHD.




Could the fact that the Lefthand window does not function when the BCU is bypassed indicate some other cause?

 

Does anyone know what the voltage from the BCU to the windows should be? I assume 12v, I am getting about .5 out of the BCU.

Any ideas why the output would be so low? Does that point to a bad ground? I checked all the main ones, plus if the ground were bad, wouldnt that affect other functions that use the same ground?

I am about to throw in the towel and find someone that sort this out. I have the entire dash apart and all the connectors exposed, so its really disappointing that I cannot sort this out.

 

When you say .5v out of the BCU, do you mean across the two pins that feed the motor, or from one pin to ground? Is that with the motor connected or disconnected?

 

If I ground the mulitmeter and back stab the wiring harness, then i get about .5v and then it goes to zero. I ran a wire from the engine compartment, the grounding wire attachment over the wheel well. I have been using that as a ground for all my testing.
That is with the motor connected. If I disconnect the connection post the BCU, the two silver blue and silver purple wires that feed the motor. This is connector 0664. If I connect power to these two wires I can make the window go up and down by reversing the polarity of the power to the two wires. Thank you to H20snow for the provided wiring diagrams, the color one is much easier to understand than the RAVE.

I get similar results when I back stab 660, the large grey plug, with wires that run to the window switches. About .5V going to zero when I press the window buttons.

It seems to me that if the motors are going to get 12 volts, or enough to operate the motors, that current must be coming from the BCU. I was not able to get anywhere near that much voltage from an of the wires out of the BCU.

I did replace the BCU with another unit that did not fix the windows, but the dash did flash and other functions did work, leading me to believe my other BCU works.

Am I thinking about this correctly? That the issue is that I am not getting enough voltage from the BCU?

 

I
Nevermind, the window stopped working.

cannot believe it. The driver side window started working today. I have no idea what allows it to work. I won't say it's fixed. Knock on wood.

Passenger side still does not work.

The only thing I did was replace the 10a fuse for the interior dash lights. Which still do not work. I am thinking about just replacing the bulbs and seeing of that helps. I had the ac control unit out, but need to find a source for bulbs. I think sylvania makes bulbs for the larger dash lights. The bulb comes out of the holder, separate from how BA sells them.

 

Hopefully you can keep zeroing in on the issue behind all this.