I have a 2018 Discovery which is factory equipped with towing package, this includes prewiring for brake controller. The car has a grey plug in above the brake pedal, which has 5 pins in the plug. NOONE, not even Land Rover retailers, can tell me which wiring harness to use or even if Land Rover sells the wiring harness and the brake controller! I would greatly appreciate any insight with this issue so I can install a brake controller asap.
Thx,

 

Give etrailers.com a try, they should be able to help you.

 

I bet it's Ford parts bin, can you post an image of your plug?

 

Had the same problem for my 2017 LR5 Discovery. The part you are looking for.....Tekonsha 3035-P....( this oem plug & play wire harness is for a Ford 150 ) and works perfectly with my Prodigy P 3 brake controller.