I am working on my gauges in a 42 Ford pickup. I have to determine which wire on my oil gauge is the power wire. Looking at the rear of the gauge, can anyone tell me if the power wire is on the left or right side ? I think it is on the left but I don't know. I can't hook up the battery to test until AFTER I get the gauges connected to my new resistor. I suspect the power is on the left. Is that correct ? The oil gauge is in the upper left of the photo. Thank you.