2007 avalanch will not strart batt. new starter ok but will not start with key

Replace your neutral safety switch on the tranny. That's usually the cause of one not cranking with the key especially if it will crank with a hot wire straight to the starter. To bypass run a wire from the positive starter post to inside the cab. Also run a wire from the positive side of your battery with a in-line fuse inside the cab. Turn the ignition with the key to the on position where the instrumentation cluster lights up. Touch the wire from the battery to the wire from the starter and it should crank. You could even run both wires to a push button switch to complete the circuit. I STRONGLY recommend that you replace the neutral safety switch instead of bypassing it. With bypassing it you run the risk of power surges and electrical feedback damaging your ECM/PCM and countless other solenoids and sensors. Hope this helps!