Power Window Wiring Issue

I've been dealing with an issue with my passenger side power window on my 1995 Chevy Astro 4.3L w/ 200K+ miles. I was told when I bought the van that the regulator motor was burned out. So I went thru the trouble of replacing the motor with a new one. Well, after installing it the window would still not work from either the passenger or driver side.

I recently pulled the motor out to make sure it wasn't because of a stuck window lift. When I had it out and used the switch at the passenger side I found the motor only worked in one direction - UP. I removed and replaced and reinstalled the lift with the window in the up position.

So I proceeded with narrowing down to see if I had a switch or wiring problem. I confirmed that the switches work on both sides. There's a wire (blue w/ white stripe) that provides a ground return, thru the drivers switch, when the passenger lowers the window or +12V, thru the drivers switch, when the driver raises the window. The wire is broken between the two switches. I checked the parts of the wire thru the door connections and the wire is good going into the vehicle. The wire is broken somewhere inside the van.

My problem is trying to figure out the route of this wire. I tried to see where the wiring harness enters into the van on both sides and can not locate the harness coming into the van, driver or passenger side.

Can someone give me an idea of where the harness on each side routes thru the van? Is it deep inside the dashboard? Does it go up and above the ceiling inside the van?

I may just be better off and wire it so only the passenger can operate the window. But I want to make sure I'm not able to fix the wire before I do this modification.

Thanks,
Glenn