T5.1 kombi tailgate interior release [Resolved]

[Drivebyracing]

Hi, hope I’ve posted in the correct section. My van is frying my brain. The interior tailgate realise switch has never worked since I’ve owned it. I thought it was a switch after wiring checks so ordered another and that one was pre opened which also didn’t fix the issue. So got one more incase as both read the same resistance. It hasn’t worked. I now also know they were the correct resistances too. Anyway, the wiring and child lock are spot on. The illumination is there and if you join the signal wire to the earth the lock opens. The switch is the standard oem 180ohm one. Can someone tell me what I’m missing? It’s not like it’s been retrofitted either. It’s all original. I’m starting to wonder if it’s a coding issue possibly and if the van has had a new BCM or something. Can anyone shed any light on the matter before I fit an aftermarket rocker switch that will kill my OCD

 

[Pauly]

If it opens when you touch the wires then the issue has to be from that point onwards ?

If it opens when you touch the wire to earth but not the other cable then sounds like you have dropped the earth feed to the switch ?

If shorting the wires opens it then why is there such a high resistance of 180 ohms ?

Is it an original switch or has someone fitted a T6 switch into a T5 (or something along those lines )?

 

[Drivebyracing]

From what I’m gathering it’s a slave switch. It sends an earth to the BCM that then triggers the main latch. If you take the plug for the switch apart it’s three wires. Power for illumination on the switch, then a signal and the earth. The switch literally pops an earth on the signal wire and it should open. If I touch the earth wire to the signal it pops the latch. The switch won’t do it itself though. The switch has an internal resistance of 180ohms which is normal and I’ve read lots with this issue but no one actually having a solution. Im really pickled. The resistance is there I imagine for the BCM to distinguish which switch has been triggered (as the interior one will only work if van unlocked etc) that’s the only thing I can think of. But am baffled why it doesn’t work.

It’s a genuine vw switch for the van and is the correct one too

 

[mmi]

If shorting the wires opens it then why is there such a high resistance of 180 ohms ?

On T6 the BCM distinguishes the switches inside and outside of the van by this 180 ohm resistance. The switches (outside=0 ohm, and inside=180 ohm) indeed are wired in parallel. Fairly confident it's the same on T5.1
Yet another coding thing.

Spoiler: Coding

Byte 02-6 = "1" : Tailgate internal release button installed (verify status in measurement block 008-3 before and after the coding change)
Byte 01-4 = "1" : Tailgate opening with internal switch enabled

T6 Retro fit OEM electric tailgate open/close switch

I know this has been discussed various times - and I've seen some good posts on wiring up a momentary switch into the power latching switch, but I have a few questions... I've got a Kombi with the electric opening tailgate (not just power latching), but has no way to open it from the inside...

www.t6forum.com

if it’s a coding issue possibly and if the van has had a new BCM or something.

Any chance to post BCM coding (VCDS, OBDeleven, Carista, etc)?

 

[Drivebyracing]

On T6 the BCM distinguishes the switches inside and outside of the van by this 180 ohm resistance. The switches (outside=0 ohm, and inside=180 ohm) indeed are wired in parallel. Fairly confident it's the same on T5.1
Yet another coding thing.

Spoiler: Coding

Byte 02-6 = "1" : Tailgate internal release button installed (verify status in measurement block 008-3 before and after the coding change)
Byte 01-4 = "1" : Tailgate opening with internal switch enabled

T6 Retro fit OEM electric tailgate open/close switch

I know this has been discussed various times - and I've seen some good posts on wiring up a momentary switch into the power latching switch, but I have a few questions... I've got a Kombi with the electric opening tailgate (not just power latching), but has no way to open it from the inside...

www.t6forum.com

Any chance to post BCM coding (VCDS, OBDeleven, Carista, etc)?

I will be able to get the coding but only once I manage to see my mate and could be a little while. Will get a copy and come back though , cheers

 

[Drivebyracing]

Right then, little update.



Just checked the coding for the BCM. The options circled above were not ticked. Ticked off and boom, switch release works .

Thank you guys. Much appreciated. I am wondering why they weren’t ticked now mind as it’s a factory kombi and switch. Plus the coding is not the standard tick options, you go into the byte section. So not just something that gets lost or can accidentally be pressed if you get me. Wonder if it’s had a BCM or something for some reason ¯\_(ツ)_/¯

Anyway though, anyone suffering the same issue the above coding fixed it for me