Okay, i was recently helping a friend test out his sub, so i hooked his sub up to my amp and then pulled out a pre-out so that only my left sub was playing and not my right. His sub was blown as i'd suspected and so i hooked everything back together. Then i turned on some music and my car started going crazy. Lights started dimming like crazy, there was very little bass, everything was just out of wack!! So i turned em off and drove home The next day, i tried unhooking one pre-out again and everything worked fine minus that one sub wasn't working.
looking on BCAE1.com, i saw that there was a chance that my amp tried to ground to my pre-out when i re-hooked it up. Do you guys think this is what happened?? what should i do?? tomorrow i am going to find someone at school that has a pre-out i can borrow to test if its my amp or my HU.
try plugging the good rca preout into bad ones spot on the amp and see if it still occurs. if it does then the amp is the prob. if not then the deck is the prob. if the deck is the prob then maybe you could use a y adaptor on the good rca wire. maybe your friends sub was shorted out and fried one channel of your amp.