HardTop 3rd stop light

[Sebav]

Hi, I have installed hardtop for my 1500 '17, I have to connect new 3rd stop lamp. Have anybody experienced with this issue? Where is the closest wire with CHMSL/stop light signal?
I rather like not pull the wire into the cabin, i see on the drawing that ther is some pink wire for aftermarket stop light but i can't find them.

 

[crash68]

If you look under the truck on the driver's side along the spare tire there will be a Purple/White that is for a third brake light.

 

[Joes1500]

When I had my leer put on , the dealer/installer tapped into the driver's side taillight. Just fed the wire through a hole in the bed right by the taillight. Easy.
If you add the electric lock so it locks - unlocks with your fob, tap into the tailgate trigger wire.
I can't remember where they found power for the interior courtesy light. Maybe the factory bed lights.