2004 Johnson 150hp

I have a 2004 johnson 150hp saltwater edition. I am haveing trouble figuring out what is wrong with the tilt sending unit I know it works somewhat like the gas sending unit. I cleaned all the connections on the gauge and tested it with + and - leads. It is showing that it is in the up position all the time but if i stick the ground lead to the ground and a + lead to the (S) on the gauge it goes down. i traced wires back to the motor and stared a test on them. (I used a 12v light tester.) I clamped on to the + on the motor and tested the black wire going into the sending unit and the light came on so i moved the arm and nothing happened. I then tested the white/brown wire and again the light came on. But this time when i moved the arm the gauge started to move also. Im not real shur on how it all works

Re: 2004 Johnson 150hp

The trim sender is a variable rheostat. That is, the resistance to ground changes as the black arm moves up and down.

BTW - They are not real accurate or reliable, when they work properly. I remove my trim gauge and replaced it with a water pressure gauge. Much more useful