Download the factory service manual and wiring diagrams. They are around if you search. The dome lights and map lights follow down the driver's side a-pillar to the driver's side left foot kick panel then out to the fuse junction box.
This guy's write up will help you:
Toyota 4Runner Maplight Mod
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2008 4Runner Sport Edition 4.7 V8 4WD
1988 FJ62 Landcruiser
President LA County Trailcrew 4x4's
https://www.facebook.com/groups/Trailcrew4x4