I've got some 12v gauges for my now 12v '49 Ford shoebox. I'm trying to connect them up to the electrical system but I'm stuck as to which wires go where. I'm starting with the fuel gauge. The new gauges are negative ground as is the car. On the back of the original 6v gauge cluster, there are two wires going into the fuel gauge - one black and one red. On the back of the new 12 v gauge there are 4 connectors: one marked ground, one marked "I", (I think that's for 'ignition'), one marked "S" (I think that's for 'sending unit') an one unmarked one. I'm assuming that the black wire going in the back of the original fuel gauge is going to the sending unit and the red one is ignition. But I'm not sure. Before I make a mistake and fry something, I figured I'd better make sure. If anyone can offer some advice on this, I'd be grateful.
I assume you have no instructions with the new fuel gauge, but the wiring is not the only consideration. The sending unit must match the gauge. Unless you have changed the original sending unit to one that is matched to your new gauge, I doubt it would indicate properly. Most gauge manufacturers post install (wiring) instructions on their website. Your gauge may have a light which could account for the additional connections. Generally one wire will be from your ignition switch, one to the fuel sending unit, another to ground, and there may be another for a lighted gauge. I would suggest you find your gauge manufacturers website and download the appropriate wiring instructions. That info should help you in wiring all the gauges.
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