There were no instructions with the gauge. The Factory assembly manual shows one way and the booklet on conversion to 12 volt shows it another. In the 12-volt conversion manual that Randy Rundle did, it shows the empty side going to the sender unit and the full side to the battery with a runtz in as well (of course this is a 6-volt) That was the way I wired my 6-volt gauge with the reducer. The factory assembly manual shows the empty side going to the ignition switch and the full side to the sending unit. I wired it according to Randy's manual and fried the gauge I think.

1953 Chevy 3600 3/4-Ton