im about to set up a trim gauge, i have a mercury mariner control box with tilt and trim. from the control box you have a 8 pin loom to engine, a five pin half circle to the rev counter with a separate black and brown also. then i have four separate wires coming from control box colours as followed light blue,lightish blue/green ( i do know these two to be for trim ) but why have some here when its already set up, then a red wire and brown wire.
the gauge its self has terminals I , S , ground & live plus
any help would be appriciated