kenwood kvt512 shuts off at high volume

I installed a Kenwood KVT-512 in a 2006 Charger today. The guy calls me back and says that when the volume gets to around 23-24 the deck powers. There was a Pioneer 5700 installed before the 512 and whoever did the install didn't us a harness. They bypassed everything including the speakers. I just wired everything back to what was there. I'm not sure where they pulled constant or accessory power from either. I tested the ground so I'm pretty sure I'm good there. I'm thinking more like a power issue. Haven't had a chance to look at it again just wondering what everyone else thinks.

Sorry the 2nd sentence should say powers off.

That's what I was planning on doing to be honest. I did a continuity test on the ground and it was at 0 ohms. When I say bypassed I mean they ran all new wire to all the speakers. As far as I can tell it was a 4 speaker system. I didn't test any of the speakers to see what they where ohming out at (not my better judgment). The only reason he replaced the Pioneer is because he broke the volume knob. Which is why I didn't test everything but like I said that wasn't my better judgment.

Well here's what I found. It's not a 4 speaker system it has the Boston Acoustics system in it. The original installer chopped up the factory amp harness and ran the dash and door speakers parallel giving it a 1 ohm load. So I ran them in series to bring it to 4 ohms. Here's the weird part though it was still cutting off but at a slightly higher volume. I set the x-over at 60hz and turned to bass down to -3 and it stopped shutting off. You can go as loud as you want. But I'm still not sure where they are pulling constant power from. I found where it was connected in the drivers kick panel but no idea what it goes to. They managed to pull accessory power from the ignition (pink/white). Either was I'm still not sure what the problem is/was 100% but it seems to be working.