I recently purchased a kenwood kdc hd545u the other week. I installed it and it worked fine and all. About a few days after wards my new sub woofer was delivered so I decided to hook it up and see how it thumps. (It's a RE MX 12' btw) I hooked everything up and thought it was ready to go. But then my amp wouldn't turn on. So checked all the wires and they were just fine, then the remote wire came across my mind so i decided to take back out my head unit to check that wire. The remote wire did not look like it was hooked up right. For some strange odd reason i decided to strip the "remote controller wire" and hooked it up to the remote wire from my amp. Then i tried turning it back on and then i notice it wouldn't turn on. So I freaked out and wired it back to the way it was before. It still would not turn on even after that. So I thought it made had messed up the deck's harness. I decided to try my other deck which is a alpine cda 9856. It still would not turn on. So i'm out of clues as to why they both would not turn on anymore. So now i'm lost but am thinking that i made had pulled some kind of plug out of place. But if anybody knows what it might be please leave your 2 cents.
Owning a cheap voltmeter could make your life really easier, your sub amp should turn on if you connect the +12 power terminal to the remote on terminal, do thiis after diconnectiong any speakers from the amp and checking all power lines, if the amp does not turn on check any fuses in the amp ( if any ) and the one near the battery, if after replacing any fuses it turns on without blowing fuses again the amp is almost certainly ok and there may be a problem with the sub or its wiring.