This week I cranked up my truck, had bass for about 10 seconds, then nothing. It wasn't even turned up or anything. Volume was probably on about 4 or 5. I believe the preouts on my HU quit working but I'm not 100% sure that I am measurin g the voltage correctly. If I put the leads on my DMM on the center pin and outside edge of the end of my RCA's on AC voltage I get a reading of 0. Am I doing this correctly?