Running board lights

My 08 Tacoma came with running boards with lights (installed at dealership) that lit when the dome light came on when unlocking the doors.
After 5-6 years they stopped, BUT would work again when in COLD weather.
Eventually, they stopped completely. The dome light still works.
Trying to track the wiring through the floor, under dash is impossible.
Any suggestions?

 

If they are in parallel with the Dome Lamp, then the connection is at connector 1E of the Main Body ECU. Pin 11 is battery fused power and Pin 9 is the dimming ground (ILE) But I'd verify the lamps first. They may have done their final illumination.

 

Thank you. I hope to get back to it tomorrow.