2005 cobalt OEM amp?

Tried to put a Pioneer 8600 into an '05 Cobalt. I used a "spare" fuse socket rated at 20 amps (according o the vehicles manual) and was also installing a PAC steering wheel interface. (gnd to gnd, 12 v switched to 12v switched, interface wire to the Cobalts darkblue (pin a9 i blieve) and then tied the WHITE/ black to 12 v switched per the instructions). Radio wouldn't power up and i found that the constant 12 had no juice. Spliced on to the RED / white 14 gauge at the fuse box for a more reliable source. Radio worked for about 30 seconds and then lost audio. I turned the car off and back on for giggles and audio came back on for about 10 seconds then no audio again. What made it really odd is that the aftermarket amp and subs lostaudio too!. I was guessing the factoryamp was shutting down but.....i dunno. ..AND THEN..... the keless entry doesnt work now. NIGHTMARE!!!!  Fuses all seem ok.

Any guesses?

the kid can't come in til friday..... i'll update ya then.

I was thinking though.... the only way I could lose audio in the OEM amp AND the aftermarket is if the remote output was faltering.... will have to wait to see.