I have one of those air compressors to inflate tires that plugs into the 12v outlet in your car. The plug on the compressor broke so I bought a new one on Amazon. The wire coming out of the compressor is like a lamp cord where one wire is ribbed (neutral) and the other is smooth (hot). The wires coming out of the new plug I bought are colored red and black. How do I hook these up? I was thinking the red is hot so it hooks up to the smooth wire coming out of the compressor?