Power and Volume do not appear to be working

I am replacing the screen on a iPod 4th generation and wanted to test the screen right after reconnecting the digitizer. The screen and digitizer work perfect, but the power and volume do not. I have not yet installed the steel mid plane. I am hopeful, but doubtful that would change what is occuring (if it is a possible ground path). I did not rip the cable or detach it from the main board. I have measured the voltage at each pin and when the device is on, it appears from left to right (with home button to the left), the pads measure 0V, ~1.5V, ~1.5V, ~1.5V and when off 0V, 0V, 0V, and ~1.5V. This has lead me to believe that the first pad is ground, second and third are volume buttons, and fourth is power button. I also measured the fourth pad with the button depressed and it stayed the same (did not go low). When I removed the steel midplane I did use a metal tool to protect the cable, because I was not aware there were exposed connections there. That being said, the voltages I'm measuring makes me think it is not damaged from that. Is there any chance when I put the rest of the parts in the volume and power will work? Finally, since the cable does not appear ripped or damaged, it seems unlikely to me a replacement would solve the issue (i.e. it is mainboard issue), agree? Trying to decide if I should attempt replacing that as well...since I'm measuring voltages, a reflow seems pointless. There does look like test points on the power cable, but not sure which is ground and which is the ~1.5v...anyone know that?