I am switching my 55 1st series GMC to 12 V negative ground electrical system using a voltage reducer for the gas gauge. I have a question about how to wire the fuel gauge properly . I have been told if you do it wrong you will burn out the gauge . My understanding is that it was a positive ground on the original system and on these applications you have to reverse the wires to get to gauge to read correctly. I have included two photographs of the gauge one of the front one of the back on the back there is one post that has some cardboard bolted to it to identify the post function, part of the cardboard is broken off so I can’t tell what the cardboard said. I myself, wrote a positive and a negative sign by the post but I’m not sure that that it is correct. I need someone in the group who is good converting GMC wiring on this gauge. Any help would be appreciated. The part about a gmc positive ground system and how that affect the conversion is confusing me. Note: attached two photos of the gauge.
