I had this same problem and it ended up being the power supply of wires from the back seat fuse box run under the sill scuff on the drivers door, this scuff gaurd rubs againts the wires and the wires break causing loss of power to the drivers door. It took only about 1 hour and no $ to fit the problem. i also had to replace the ddm fuse in the fuse box under the back seat, this is the fuse for the drivers door controls.my 2005 trailblazer has no power to the drivers door. i have checked all the fuses and i can't figure out what the problem is. does anybody have any ideas. it looks like the wireing harness to the door looks ok.