Re: Hooking up trim gauge... Evinrude 1978 115 HP engine.
You are correct in that it is a variable resistance. I'm assuming the wires you speaking of are coming from the sender are are probably both black. If this is so then you would connect either wire to the S terminal on your gauge and the other one to the ground terminal. Connect the I terminal of the gauge to a 12v positive source that is only on when the ignition is on. The I terminal of another of your gauges is usually a good place for this. Ground terminal to another gauge's ground terminal and you should have it. BTW, if one of the wires is tan/white it would connect to the S terminal and the other wire to ground.<br /><br />To adjust the gauge the sender is rotated until the gauge needle is at the center mark when the motor is at the center trim stop hole.
