[77newell]

Mike: the way I would proceed (which is imaginary since it really helps me to see how things are arranged) is to find the power supply wire and check the voltage on it with and without the light on. This attempts to determine if the spot of resistance is before or after the connection to the relay. You will want to measure the voltage on both the female and male parts of the connection as this tell you if the connection itself might be the bad spot. If the incoming drops voltage when the light is on, then I would head to the fuse supplying this circuit and check the voltage on each side of the fuse, I've had fuse holders build up resistance.

In any case, what you do from the first step of checking the voltage at the input to the relay is work your way from that spot outwards in the circuitry until you run across an unexpected voltage drop. It could be in the relay (unlikely in my opinion) or in a wiring connection (most likely)

Let us know what you find and we can help from there. It would also help to draw a wiring schematic of the system as you work on it. With wires seemingly going everywhere I find it hard to keep track of it all and know where I'm at so I tend to draw diagrams as I go. The "black boxes" of the relays make it difficult to follow the circuits through them, but with a little persistence it can be sussed out. The more we know about how the system is put together the easier it is to troubleshoot.