I'm rewiring 53 chevy 1/2 ton.It is converted to 12 volts already. Found a componet about 3/4 diameter by 2" long. one end is connected to amp gauge the other was not connected at all.Does it go to gas gauge? Gas gauge was not working before it started to rewire. There is a number on it. 7257919, .5MFD, 200V.D.C. What ever it is do i need it? And how do i test it?