I bought a cheep trim gauge for my boat. I am trying to wire it up before I drill the hole in the dash. I hooked up the white with light brown strip to the signal post. Ground (black) to ground and purple to ignition. I turn on the power and the ignition switch and move the motor and the gauge stays all the way down. (its all the way up before I turn on the ignition switch) What is it I'm doing wrong? Or what am I missing?