I'd like to install some footwell LEDs (all four seating positions), and have them be controlled the same way as the map light. That is, on when doors open, slowly dimming down after use, as well as controlled by the map light switch.

I've been digging the FSM's and the BCM pin 4 (interior lamp) appears to be connected to some "interior room lamp harness", where the map lamp is positioned as R15. Does anyone know where this harness might be located? The BCM is easily accessible, so if I could wire things there directly, that'd be great. Or if anyone else has installed footwell lights and have them controlled to some stock/built in power switches, I'd appreciate it if you shared your experiences...

crack open the door, and attach to the light thats on the bottom of the door. then run the wire back to the driver foot well and go from there.

thats what i would do.

Just by the OEM footwell leds from everythingg35.com that plug into the stock plugs on the passenger side footwell.. Problem solved

^Agreed. Plug and play FTW