Hardware:
5F0927143 WHS - ESP Button
000979009Е x 2 pcs or just 4 terminals pins from ebay for cheaper
000979046E - ABS control unit cable. Same, we just need the terminal pin.
Cables. You can put original colours
3 Meters (you can measure from the ABS control unit to the switch) Purple-Green* for the ABS control unit
0.5 Meters Brown* for ground
0.5 Meters Grey* for switch illumination
1.2 Meters Black-Green* for 12v
Thanks to www.clubseatleon.net user Romera for the cable tutorial and demonikx for the references of the parts.
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There are two ABS cable connectors, there is one with 38 pins that i think are fitted in early production years and then the 46 pins that most Leon 5f have. Mine is a 2017 FR model so if yours is different I do not know for sure but it seems that in the 38pin connector you have to connect it to pin 4.
The ESC switch sends an +12V signal to the ABS control unit to trigger ESC on and off as is in your infotainment ESC setting. If you have two "OFF" settings you access the second one by long pressing the switch.
Tutorial:
First locate the ABS control unit at the back left side of the engine bay (1)
Remove the ABS control unit cover by pulling up the little tab of the plastic cover at the bottom and remove the cover.
Remove the connector and with a flat screwdriver remove the "cover/lock" of the connector to have access to the cables inside. Be careful when reinstalling the "cover/lock" cause there are some plastic bumps you have to slide first at the rear of the connector and then clip the front.
Locate pin 39. Normally there is a plastic insert.
To remove it there are some plastic tabs that you have to move.
I tried to move the tabs but they break on me, so with a small nail I moved the purple plastic from the groove in the left and moved the purple plastic inside to the right and a little purple bit appeared at the right.
Remove the grey plastic insert and put your cable. DO NOT PULL ON OTHER WIRES. Then push the purple plastic bit (that appeared at the right) to the left to lock the pins in place.
Root the cable to the switch inside the car. For LHD cars, there is a way behind the battery. No need to remove the battery, just unscrew the battery holder and pull the battery to make space.
Then remove the glovebox to have access behind the centre console and push the 3 switches from behind. If easier for you, unclip the clima panel to remove the switches.
Now just make the connection to the red connector (ESC-airbag):
Pin1 of ESC button (red connector) brown cable* to pin 1 of the MODE switch (black connector) brown cable
Pin6 of ESC button (red connector) grey cable* to pin 2 of the MODE switch (black connector) grey cable
Pin7 of ESC button (red connector) purple-green cable* to pin 39 of the ABS connector (if you have different connector from the picture above, it's probably the 38pin connector and you have to use pin 4)
Pin 8 of ESC button (red connector) black-green cable* to fuse 34 for +12v. I did it with a quick connector and a 7,5A fuse.
(The tutorial say to connect Pin8 of ESC button (red connector) to pin 9 of the MODE switch (black connector) grey-purple cable but I didn't have any cable there)
* not necessary to use this specific colour.
