Finally updated my speedometer - it's been annoying me since I picked-up the car. Mine is a 2017, built March 2017. I was not able to find a grey/black connector anywhere on my car.

By the way - the purple/grey and black connector has 12v on it and is for the 12V outlet and intercom when fitted. If you short those two terminals together you'll blow a 15A fuse :-)

However, I did find the black/grey wire in one side of the 20-pin black connector above the fuse box. The other side of the connector was empty. I stripped a wire, pushed it in the open connector location, and hooked it to an old doorbell button, and then connected the other wire from the switch to the black ground wire at the intercom connector (but any ground will do). Simple, didn't have to strip any wires or solder anything, and worked perfectly.

I did find that the speedo came up in "Input" mode, and I had to cycle through to get to "Pulse" mode.

The suggested 004045 setting from the article for the Blockley's - on my car - was too low and resulted in speedo readings still 3% to 4% high. I added 3.5% to the 004045 to get to 004185 and the speedo is spot-on accurate now.

Pics of the connector with the black grey on one side and open terminal on the other:

[Linked Image]
[Linked Image]
[Linked Image]

Last edited by truckin-on; 13/07/20 08:10 PM.