Barn-door To Tailgate Conversion
- Thread starter Ads_Essex
- Start date
I am not sure how this would be possible or for me to check. As I mentioned I did goto the trouble of running the 2 wires all the way back to the bcm. I am pretty sure the switch in the tailgate the soft close switch is just shorted to ground in order to send the message to the bcm.
But the issue will be somthing like you suggested. So if you know anyway I can check this I will
I mean any fault codes now after a couple of lock/unlocks, playing with tailgate handle at different tailgate positions, etc.
Correct - that's why I'm thinking when the door contact switch opens (=door closed-closed) the BCM can't see the handle switch anymore.
Just the same fault as before now after a while of testing. As nothings really changed to as I had it before.
You must be right about this central locking and the switch having issues. But I don’t understand what would be causing it nor what to do in order to cure the problem. If you have anymore suggestions I will keep trying.
You must be right about this central locking and the switch having issues. But I don’t understand what would be causing it nor what to do in order to cure the problem. If you have anymore suggestions I will keep trying.
So, the tailgate handle switch was obviously a new wire - connecting into BCM pin 23 (black connector).
Can you tap on that wire and simply short it to ground - and verify with VCDS measurement group 008-4 that BCM recognises it (the red box showing as "Active"), also in tailgate position closed-closed. If still not seen in 008-4 perhaps need cut the wire (to isolate tailgate wiring completely) and short to ground just the BCM end of the wire.
If still struggling please measure voltage (against chassis ground) on that wire in different tailgate positions - both handle switch not pressed and pressed.
Earthing the wire (close to BCM without tailgate wiring involved) is just to verify that the BCM registers it correctly as "Active" in 008-4 even when tailgate is in position closed-closed.
The would prove there is a wiring issue inside/close tailgate. The earthing is not meant to be a permanent solution, only a measurement.
Ok so I did some further testing. I will try to describe what I did. I did also make a video to show the behaviour of the locks whilst carrying out the test.
So what did I do
I connect to the the wire which goes to the tailgate handle soft switch. The switch we’ve been talking about that just needs to go to ground to activate. I had a good length of wire so was able to earth it on the chassis near the sliding door away from earth point it uses at moment.
What to point out
What I should point out at this point is the earth is the same which is used in the tailgate catch which registers if the tailgate is closed and open.
So open closed status
Now when I carried out the test I got slightly different results. Firstly though earth the wire would still show in group 008 box 1 either open or closed as it still triggers the central locking for some reason every time. So I still have to do the same thing , which is unlock the van with remote and then quickly try to open the tailgate. It will then power the actuator to release the tailgate. Group 008 box 4 show active as I ground the wire. So same results as before.
So now closed closed status
Now this is where I now also get a reading which I don’t get when using the earth in the tailgate. Using the earth on near the sliding door. It now does register the button press of the handle and shows active when pressed or in this case when I earth the cable. This has never happened before and when I test agin with earth in the tailgate it doesn’t register the button press with status closed closed. Unfortunately what it still doesn’t do is power the actuator to open the tailgate.
But this is a significant step forward
- obviously need to get button to register also with earth in the tailgate. Missing earth or wiring issue?Did you bring a dedicated wire through the bellows for tailgate earthing?
Another or the same wiring issue as above???
Yes it seems that with earthing the tailgate switch it will register the button press even when closed closed status in the messing blocks. But that still doesn’t explain why it still won’t open the tailgate even when it knows the correct status ie closed closed.But this is a significant step forward
Did you bring a dedicated wire through the bellows for tailgate earthing?
Another or the same wiring issue as above???
So yes I took the correct esparto for the tailgate and also checked with multi meter that I had continuity with the earth going to the tailgate and the chassis. Also other things in the tailgate are happy to use the earth.
So I am not sure what else to do. If I go to the trouble of running another earth to the tailgate for example it still wouldn’t act correctly and make no actual difference unless there’s something I can change in the vcds?
Also I still have no idea why it keeps activating the central locking when the handle is pressed. Surely this isn’t normal?
Just thinking that something dislodges at closed-closed because the solenoid definitely should pull then.
Well, perhaps you could try the following - keeping tailgate open and manually operating the tailgate latch.
Ignition off, no keys in the barrel.
By using VCDS set up monitoring of BCM groups 006 and 008.
Leave the tailgate open and "simulate" door switch open/closed by operating manually the latch mechanism in the tailgate.
Verify by VCDS open-open and the handle button are registered
Verify no solenoid pull (as tailgate is open-open)
Push the latch tongue with screwdriver ONE click inwards
Verify open-closed and then press&hold the handle button - verify the button registered
Verify the solenoid pulls and doors return back to open-open
THEN
Push the tongue with screwdriver TWO clicks inwards
Verify CLOSED-CLOSED, and now press&hold the handle button
Verify by VCDS the button is registered
How about solenoid now???
If no solenoid action please set VCDS to monitor ONLY group 011 It's IMPORTANT to have only one group monitor to have high enough sampling rate to catch solenoid activation pulse seen in group 011-1.
Repeat the closed-closed and press the handle button.
A short flash of "OK" in 011-1 ???
No, not normal.
Desperate times. It seems that you have swapped the door switches in the wiring. Actually BCM expects to see them as as Closed-Open
Anyways, don't know if that's a significant thing.
