I have 2001 impala with the same problems about a year ago. I added the toggle switch and the procedure worked great. The car sat for a couple of months and ofcourse the battery died, i charged the battery and now im having the same problem again. I try to start it but nothing happens even with the toggle switch in the off or on position. The information center on the dash does not work , the interior lights and radio dont work it seems like im only getting partcial power because the windows seem to be working. When I turn the key i can hear the fuel pump working and a clicking noise coming out of the fuse box located on the driver side of the dash.