Thanks, I gave it a look and did not see any disruptions. I will research the continuity check, I have not done that before. Any ideas on where it is most likely to fail if it is affecting both sides? I dont really see anything common except the BCU, and a :"new" one did not fix it.

 

You have spent a bunch of time trying to figure out what could be causing both to fail and only look for those things. There is nothing wrong with starting off a troubleshooting session that way, but at some point you have to throw out all assumptions and go back to basics. See how it all makes sense AFTER you have figured out what's wrong.

I think you said above that you see 5 volts at the motors when you try to operate the windows. What do you see on the rears that work fine? 5V or something else? 5V at the motor; what do you measure at the BCU? if it is different then you have something happening between those two points. Find it. Don't try to think if it is likely, just find the failure point. Find things that you CAN know, like the active voltage at the working windows, at the BCU, at all other points. Having a working model is priceless when troubleshooting.

 

Thanks I have not checked the rear doors, as they seem to work fine.
New development is that the front sunroof will not close, opens fine, does not close. Rear sunroof and windows are still fine.

I have been pouring over the RAVE to find the correct pins to check. There is no pin out for the BCU unfortunately, only the plugs and then I have to trace that back to the BCU.

Given the sunroof is operated by C0785 connector and it is not getting the signal to close, i think it must be a function of the BCU sending a signal to both the windows and the sunroof. Still trying to find the connection from the BCU to the C0785 connector.

It looks like the pins to measure voltage at that should power the windows at C0660 plug into the BCU is
1 LF Down
2 RF Down
18 LF Up
19 RF Up

Connector C0064, the box mounted on the side wall.
1,4,6,7 Should have voltage also.

Painful learning curve, and I was just thinking how reliable this truck has been. I had run out of things to fix. I jinxed myself for sure.

 

Another thing to do when measuring voltages such as the 5v at the motor is to measure between the terminals to see the 5v, then measure high side to battery pos, then measure low side to battery neg. This might tell you that you have a problem in the feed or in the return wire, or both, or maybe some ground strap elsewhere in the truck. Again, it can help a lot to check the supposedly correctly working rear windows to establish a baseline.

 

Thanks, what is the high side and low side? I betting it is a ground issue, from earlier advice. And there is not really a common point the feeds both windows, left and right that I can see. the BCU does not appear to be the issue, I replaced it and no luck, there is no other common item between the two sides that I can find. I could be completely wrong, but it seems that in all my reading that the only place common is the BCU.

 

Most things in an auto are fed 12v to turn them on, with the other side of the thing connected to ground. Something like a power window motor are fed both sides of the device so that the controlling device can reverse the polarity to allow movement in either direction. In the case of a motor, CW or CCW rotation. The two wires of the window motors are fed power in one polarity for up and the other polarity for down. When referring to high side and low side, we are referring to whichever wire is driven toward battery positive or battery negative respectively.
Don't bet, measure.
You still seem to want to deduce the problem; you have working rear windows and a multi-meter. I recommend you measure like points on the rears and fronts and see where you have different measurements. Take your measurements with all connectors connected. Backstab your connectors. (To backstab is to stick your meter probe in the back of the connector on the wire side to probe the signal while everything is connected so that it could operate if working. If your probes are too large to fit, use pins to stab and then probe the pins. Alligator clips help here.)

 

OK, sorry, I just looked at the wiring diagram for the rears and learned that they aren't controlled by the BCU, just switches directly. There is little that the comparison of rear to front will tell you. That said, the troubleshooting thoughts are all still valid. A good first step is to measure voltage at the motor and at the BCU and compare. Measure high side to bat and low side to neg bat is also still good info. Check on BCU pins that you see the switches closing. If you see different voltages at the BCU than at the other ends then you have a wiring problem. BTW, have you ensured that your battery is strong? A weak battery/charging system negates all testing so far.

 

I was able to work through up to the BCU today.

If I run power to the plug C0664 I can operate the window up and down. This is the plug that sends the signal from the BCU to the motor via a couple other connectors. So my issue needs to be between the switch and the BCU. I have tried other switches, no luck.

When I check voltage at the prongs on the BCU that C0664 plugs into, there is little to no voltage at those prongs. Knowing that BCU is not the problem, my issue must be the input into the BCU.

Looking at RAVE the input is Plug C0660, the grey one in the BCU, #1 pin gets 12 V, the #2, seems to sometimes get 12 V. It read 12v once and then zero. Backstabbing the connector seems to work best, but the probes are still fairly large to be certain that I am getting enough contact to say for sure that it is not getting voltage consistently. I grounded the multimeter to the car battery. Pin 18 and 19, I did not get any voltage when I hit the window switch.

If I pull that connector apart, will all the wiring fall apart on me? It appears that my problem is between that wiring harness and the switch. Or, do I need to ground the multimeter to the plug somehow, is that causing my lack of voltage reading?

Front right window up
The right window switch up contact is connected to pin C0660-19 on the BCU by a BU wire.
When the switch is set to the up position an internal supply from the BCU flows along the
BU 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 C0660-19 and uses this input as
an up signal. The BCU routes power from the permanent feed from pin C0664-7 to pin
C0664-6, from pin C0664-6 on an SK wire to connector C0326-2 on the RH front window
motor. The motor is energised and drives the window mechanism towards the up position.
The front right window lift motor is earthed via an SK wire to connector C0664-2 on the BCU.
The BCU completes the earth via pin C0664-5 on a B wire to earth header C0018 LHD/
C0017 RHD.

 

D2 Front window controls

Start with a backstab jumper from C0660 1,2,18 &19 to GND (one at a time). If your windows work that way, then you have a wiring or switch failure. Then move to C0242 3&4 and C0321 3&4; jumper those to GND (again, one at a time). If the windows still work, then jumper 242 and 321 pin 1 to GND and try the switches. If the windows still work then your ground point that those switches connect to is bad. Fix that.

- GND is a GOOD ground. Don't assume that any old point will work. Find a good solid connection to gives GOOD contact to BATT Negative.
- Auto wiring diagrams are notoriously unreliable. Remember that as you do this work.

 

- Auto wiring diagrams are notoriously unreliable. Remember that as you do this work.[/QUOTE]

Do you think this is the case with the Land Rover manuals. I’ve found them to be very good with anything I’ve done so far.