I replaced the head unit in my 2007 Yaris yesterday thinking "how hard could it be?" Apparently there's more to it than I thought. There's nothing fancy in my car, no subwoofer or anything other than the new head unit. I bought the correct wiring harness and used butt connectors to connect like wires to like wires and everything worked great. This morning I go to get in the car to go to work and the battery is dead.
When I hooked up the harnesses, there were 2 wires on the Metra harness that did not have corresponding wires on the Pioneer harness. Blue for power antenna (my car doesn't have a power antenna), and Orange/White for dimmer (ceiling light seemed to be working as normal as it was dark by the time I was done). On those wires I went ahead and crimped a butt connector onto them so there would be no exposed copper. The factory radio also had 3 plugs going to the back of it where the Metra harness only has 2 so I've got a free plug hanging out in the dash. I'm sure it's something simple but this is my first self-install so I'm obviously missing it. Any help would be greatly appreciated.