So my driver side window isn't working. I'm thinking it's probably the switch, as it usually is. So I buy a brand new oem window switch...nothing. At this point I'm thinking it's probably the regulator. I buy a used, good regulator...nothing. No noise from the motor or anything, but the passenger side window does still work if the driver side is plugged up as it should. Any ideas?

 

I don't know the answer but these were some of the questions I asked myself when I was troubleshooting mine:

You're positive it's a good used regulator and you proved this by testing it against a known direct power source? What happens when I rig up the 12v from my used power supply direct to the regulator? Now what happens when I take that power source and enter it from the output side of the switch instead of the input side of the regulator? Now what happens when I place that same power on the input side of the switch? Where does this...**** up...basically.

For me it was the switch buttons being corroded.

 

Check your window regulator to make sure it's good. If both regulator and switch are good, you have fault somewhere in your harness/wiring.