Have a look here ---> Traction Control
Traction Control - ESC/ASR & HDA switch retrofit
- Thread starter Chickybumps
- Start date
As per diagrams posted by @Robert :
Connect blue/white wire (pin 5 from TC button) to ABS unit pin 4 and yellow wire (pin 5 from HDA button) to ABS unit pin 8?
You don’t require to connect to pin 6 on ABS plug as long as you can bring 12V DC after ignition to pins numer 4 on both switches. So in total you need to run 2 wires to Abs plug, one for TC and one for HDA.
This thread is great, it’s amazing how much progress has been made, and I’m grateful to the guys who put the research and experimentation time in and are then willing to share the knowledge 
I’m particularly interested in the Hill Descent function, though I may as well do the traction control mod anyway at the same time, but from reading the thread so far, it seems there might be an issue activating HDA with the lower spec console. Unfortunately I have this and just wondered if anyone had got to the bottom of whether it’s still possible?
I’m particularly interested in the Hill Descent function, though I may as well do the traction control mod anyway at the same time, but from reading the thread so far, it seems there might be an issue activating HDA with the lower spec console. Unfortunately I have this and just wondered if anyone had got to the bottom of whether it’s still possible?
Analysing the wiring diagrams I was expecting that HDA button will illuminate when this system is active. But instead Instrument Cluster indication light was/is used via CAN(at least in my case).
The best thing to do is to check and see if HDA icon is present in your IC.
If you use any flash light(torch) and you light up the area as per below
you should be able to verify that before you begin this retrofit.
If this icon/indication light is missing or there is no LED on the IC PCB I would imagine that HDA switch should work as indication light. Only 1 extra wire would need to be run from ABS unit to the HDA switch(grey one as per the wiring diagram).
The best thing to do is to check and see if HDA icon is present in your IC.
If you use any flash light(torch) and you light up the area as per below
you should be able to verify that before you begin this retrofit.
If this icon/indication light is missing or there is no LED on the IC PCB I would imagine that HDA switch should work as indication light. Only 1 extra wire would need to be run from ABS unit to the HDA switch(grey one as per the wiring diagram).
Same for me.
VW changed the wiring diagrams, now the extra cable to the illumination of the Switch is gone.
I think it was a feature that never was implemented fully.
I tried with coding to "Enble" this feature for Button illumination, but no luck.
I would assume that every T6 Cluster does have the LED like in Roberts Picture.
But even if not, i think HDA will still work, but that i can test.
I can switch my Cluster from T6 Premium to T5.2 Premium Cluster, and the T5.2 Cluster does not have HDA LED.
I will test and report back.
I've ordered the pins and wire to add HDC and TC to my van. I've not looked under the bonnet yet so it may be obvious, but where do you route these extra wires through the bulkhead?
Happy working there.
It is a pain in the ass work to get the cabling done.
The Cable is going throught a already hole beetwin indoor's and the Engine. I made a smal hole into the plastic part that was closing that hole.
Tricky part is to access the ABS Connector.
I dismounted everythink around it.
But i am Left Hand driving
With Right Hand driving it is probably easier ?
It is a pain in the ass work to get the cabling done.
The Cable is going throught a already hole beetwin indoor's and the Engine. I made a smal hole into the plastic part that was closing that hole.
Tricky part is to access the ABS Connector.
I dismounted everythink around it.
But i am Left Hand driving
With Right Hand driving it is probably easier ?
Well, it was approx. 30 € for T6. But now it is in Finland standard on all T6.1, so the price is not listed any more.
The HDA (option "UG5") is 115 € but available only for 4Motion.
Seems that Side Assist is now available also on long wheel base models.
@Robert Can I just confirm that's all thats required? Other than for switch illumination, there is no need for an ignition on 12+ve supply. The power supply comes direct from the ABS unit, from pin 6, through the TC switch and back to the ABS unit pin 4? Plus coding. And that this would mean the circuit is already correctly fused, through existing ABS fuse?
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Where is the best place to source these parts?
I bought 2 new switches (7E0927134B & 7E0941435D)and 2 second hand plugs(4D0971636? I had to trim some notches)
with 000979009E pre-crimped wires and paid in total approximately €40=£36
Then everything wired in and applied the following coding to the ABS unit.
Traction control off - Byte 15 bit 6 from 1 to 0 (already mentioned here by Dennis)
Hill descent assist - Byte 6 bit 1 from 0 to 1 & Byte 14 bit 6 from 0 to 1
VOLKSWAGEN genuine spare parts shop with part number and catalogue
Also by having GB VAT number you could avoid paying 19% German VAT, but only utill the Brexit.
Also by having GB VAT number you could avoid paying 19% German VAT, but only utill the Brexit.
Absolutely correct mate.
This is such a great thread and upgrade, it's just found it's way to near the top of my list.
I rang my local VW parts guy in Scunthorpe and told him what I planned to do. His reaction was telling of his interest...
"Well, obviously I haven't got a clue what parts you'll need"
Cheers for that mate. Thanks to @Robert and this thread I do. 22 GBP+ VAT for the parts but he wouldn't post them to me so I 'll source them locally.
I told him I'd got the info of a thread on a forum and he tried to tell me that to wire it in would cost north of 6k!
I rang my local VW parts guy in Scunthorpe and told him what I planned to do. His reaction was telling of his interest...
"Well, obviously I haven't got a clue what parts you'll need"
Cheers for that mate. Thanks to @Robert and this thread I do. 22 GBP+ VAT for the parts but he wouldn't post them to me so I 'll source them locally.
I told him I'd got the info of a thread on a forum and he tried to tell me that to wire it in would cost north of 6k!
Today I finally received all the parts and got TC On/Off and HDA switches fitted/connected and can confirm both functions work perfectly fine! Thank you very much all of you for this thread. Special thanks @Robert for helping me with the wiring diagram.
Codding was done by a local specialist for £20 according to the instruction in this thread.
Any tips on removing the cover off the plug to access the pins? I've got the plug off the abs module but I don't want to break the cover taking it off.
