1980 johnson tilt/trim gauge issue

[buzz89]

1980 Johnson 75 hp Stinger. The tilt trim gauge doesn't move when the motor goes up or down. I removed the wires from the gauge and tested and it moved both ways. I replaced the sending unit that was on the motor as it was bad. I installed the sending unit but the gauge still doesn't move when using the up/down switch. Does the "horn" and purple wire have anything to do with this. Does anyone have a accurate tilt/trim relay box diagram as maybe something isn't wire correctly. The motor goes up and down just fine I just can't get the gauge to work. Does the key need to be on when trying this as well? I have had the key on and it makes no difference. Any help would be great.

 

[Joe Reeves]

The key needs to be ON in order to apply 12v to the "B" terminal of the gauge.

To check the gauge, with the key ON, ground the "S" terminal of the gauge... That should peg the needle proving the gauge is okay.

To check the sender... hook up a ohm meter to the two wires of the sender, then move the sender's lever up/down. That should create a smooth movement of the meters needle/reading back & forth.