Auto On/Off LED Courtesy Light Wiring Question

I Have LED's hooked up all around the undercarriage of my car to serve as a courtesy light when I unlock the car or come near it. I would like to tap in to the dome light or any other light that comes on to draw power. I don't want the lights to be on while driving, so hooking it up to the dome light seems like the best option.

I have also read in an older post someone may have hooked something similar up to the "Key Slot" light wiring under the dash - that would be preferable as it is easiest to access.

Does anyone know which wires to tap?

Many thanks.
B