this sounds dumb, but before i replaced my amp, i tried to prolong the old one a little. i put a zip tie around the amp longways (putting pressure against the connecting clip and i guess making a better connection) and tightened the hell out of it. this fixed the problem for like 6 months untill it finally went and i bought a new one


edit- sorry to hear youre still having trouble with the driver side window. sucks man