For about $20 you can also buy a remote inspection camera, or endoscope. It’s a tiny camera attached to a long stiff cable. I have one about 10ft long the transmits to my iPhone. I’ve used it to help fish wires etc in the sticks and bricks house.
Hopefully you already have a harness or wires nearby. If you do but aren’t sure what they are, you can use a pin to probe through the wire insulation along with a voltmeter to see which is hot or switched. You should cover up the pinhole with electrical tape when done. ONLY DO THIS ON LOW VOLTAGE WIRES, do NOT try this with yellow or white romex, those would be 120v!
