I just picked up a Defender 110 1996 and would like to install flood lights to the front of the car. The previous owner seems to have wired lights for the car -- inside the car, I found a switch connected to a Helia relay, spliced into a brown wire that goes into a larger loom of wires into the firewall of the car. I cannot really access those wires without pulling the entire dash out.

Is there a smart efficient way to figure out where those wires are wired to? I checked the front of the car and I can't quite find any wires there. I do see several bunches of wires coming out from the firewall plugs in the engine compartment.

 

You can get a wire chaser like this to help follow wires: