The blue wire that comes out of the tuner module is intended to be connected to your power antenna. Its main purpose is to raise and lower the kind of antenna that raises and lowers, whenever the radio is on. In other words, it allows you to listen to MP3s with the antenna down. (For example, driving through an automatic car wash while listening to "On The Run" from Dark Side of the Moon, highly recommended.) Then, when you switch to Tuner, the line goes hot and your antenna goes up. (It can also serve the purpose of supplying power to a powered antenna signal booster.)

Do not connect that tuner blue wire to your amp power blue wire. I don't know what happens if you do that, but I'll bet it'll blow a fuse or something. Maybe that's what happened. Check all your fuses, including car fuse-panel fuses and inline fuse blocks in the player wiring.