I was hoping to be able to have a water temp gauge on a boat I've built with the mariner installed. It has a new commander 2000 controller with a new 8 pin cable connected to motor. I understand the tan colored wire is the sender for this gauge. The issue is that there is a single tan wire at the 5 pin connector at the controller and a single tan wire at the 8 pin connector at engine. Both have female bullet connectors. Which of these two tan wires should I use as the sender or does the one at the 8 pin harness have to be connected to the engine first?