What makes finding corroded wires difficult is that LR knew they were building a mobile computer and for the most part, used computer wire in the control circuits. This means super fine such as 26 gauge so often the wire corroded within the insulation and hence one cannot see anything. About the best one can do is try and find the breaks by feel - not a very good way. The good news is the fix is just normal wire spliced in where the bad stuff was removed.

As to aftermarket, as long as the whatever is made in the EU, I figure it is good or even better than OEM. Far East sourced is another matter. As it turns out the Ford / Motorcraft / Land Rover brake switches are made in either Malta or Cyprus.

The Ford / Motorcraft brake switch part number is per the jpg of the box below, SW-6572 or 7E5Z-13480-A. What I am saying is the LR dealer may not have one is stock but a Ford dealer will and the price will be less but still OEM quality.

 

This is a good switch install link.
https://landroverforums.com/forum/lr...e4/#post430840

Note when installing the switch, do not press on the brake pedal - something bad happens to the new switch related to plunger position.
Also do not fool around with the new switch, just install it. Putting an ohmmeter across the contacts and pushing the plunger will suggest the switch is no good. Wrong, it is just that the plunger is already depressed for installation purposes and when you twist it re the install, the plunger unlatches and then the contacts work as they should. This is why one does not push on the brake pedal until after the install is completed.

Taking the removed switch apart is easy and is a good idea as one can check to see if there is the black dust within. My first switch removal, there was dust, the second time, none but the whatever problem was resolved.
A new Land Rover switch part number is XKB500110 and one hopes that means better than the earlier ones and was not just to hide a price increase.