I have a 54 Chevy 3100 P/U. The original gas gauge was not working. I suspect the previous owner burned it up when they converted to 12v. I can put a volt meter on the lead wire and it reads 12v to ground. I purchased a new 12v gauge. When I installed it, the needle on the gauge swings past full and buries the needs almost 180 degrees opposite the half tank mark. If referencing a clock, the gauge should read between about 10 o'clock for empty and about 2 o'clock for full. My needle goes to about 5 o'clock, way off the scale. Nothing changes when I disconnect the sending unit. The needle does swing back when I disconnect the lead to the gauge. Do I have a bad (new) gauge, do I have a bad (miss-matched sending unit, should be 0-30 ohms unit) or could I possibly have the two wires on the gauge reversed?
My car has 100000 miles.
My car has a manual transmission.
You would need to see if the sending unit is shorted to ground. If you test it with an ohm meter you should get somewhere between the 5 and 30 ohms. If you are getting 5, then the gauge will be at full; and if you get 30, it should be at empty. If you are reading too low on ohms, then you have a shorted sender. If you'd like some help looking at this, a technician from YourMechanic can come to your car's location to inspect your electrical system in person and let you know how to best proceed.
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