Looking to hard wire my radar into the mirror or overhead. '18 Disco HSE Lux. Anyone done, and can advise on which wires they tapped into? Thanks.

 

I found an unused fuse location behind the glove box. Fuse location 51 had no fuse and was listed as accessories. It is energized only when the ignition is on.
The top of the fuse holder is the hot side and the bottom is the fused side. So if you insert a fuse you can take fused power off the bottom. I did not insert a fuse - I took power off the top of the fuse holder and put an inline fuse an inch or two away. I used a spade lug cut to a narrow width of about 1/8 inch to insert into the top where the fuse would have gone.

I ran the wire to the right and then under the rubber moulding that runs up the door pillar. At the top of the door pillar I crossed over to the windshield and then tucked it under the edge of the headliner where it meets the windshield. I wrapped a bit of electrical tape around the wire so it would stay in place behind the edge of the headliner. The wire runs along the headliner from right to left, behind the rear view mirror cover (it just tucked in - didn't remove the cover) and then used the tape again just left of the rear view mirror. Then it drops down to the radar detector which is just left of the mirror. My wire is quite thin - it's telephone wire because my detector uses an RJ11 phone cord for power (Escort). I think it took me longer to write this than to do the installation.