SX225TXRY question for Mr. Rod Bolt

[boscoe99]

The power trim and tilt motor parts catalog illustration for this model indicates four wires coming from the motor. Sky blue, grass green, black and white.

The wiring diagram manual however only shows the blue and green wires.

I believe the black wire is an aux ground of some sort. For a thermoswitch maybe? Yes or no?

What in heck is the white wire used for?

Thanks

[rodbolt17]

never saw a white wire, I have seen a 10 ga,black,green,blue and an 18 ga black.
it was a bonding issue best I recall.