Here is a copy of the wiring diagram for that unit. It shows for jackplate, but T&T should be the same.
Auto supply stores like NAPA, Carquest, Autozone etc. should have relays that will work.
Re: Problems with the Quick release bracket for my Lowrance elite 4x
Re: Problems with the Quick release bracket for my Lowrance elite 4x
It's a bayonet type mount. Place your palm over the top of the unit with your thumb pointing down over the screen. Then, with your middle and ring...