I have a brand new (well older model, but new nonetheless) Pioneer Premier DEH-680MP radio in my car, but she's having problems. When I first hooked up the radio, I noticed that the voltmeter was reading a bit low; hovering between 10-11v. Sometimes the voltage would drop below 9v and the unit would shut off and come back on after a couple seconds, and happened more often at night. When I added my sub, I ran a 12v constant (because my radio harness = pwned and doesn't have a working 12v constant) from the battery at the same time I wired up my amp, and also improved the ground. The radio would now read between 11-13v... more normal. At night I still get voltage dropping on the HU every now and again, and sometimes it will turn on and off for like 2 mins. My 12v switched is reading above 12.5v at idle under a load (A/C, headlights, and stereo on) and my capacitor (yes I know, you guys don't like em but screw off) always reads above 13v even under heavy electrical stress. It is really getting on my nerves. Could it be something inside the HU reading the voltage incorrectly.