[Airjer_]

Or unplug the window switch apply power and ground to the brown and dark blue wires. I think up is power to dark blue and ground to brown.

And easy way to check the switch with a test light. Back probe the dark blue wire. With the switch in the up position there should only be power on the dark blue wire. If there is power on the brown wire the switch is not grounding the window motor. If there is no power on the dark blue wire the switch is not providing power top the window motor. Vice versa for the down position.