Need help diagnosing odd Power Window Issue

When I got my 99 with 80k miles, both power windows didn't work from either the drivers or passenger side switches. Power locks, memory seats, heat all ok. Now that I've sorted all the other larger issues with the car, I'm tackling the small stuff.

Here's what I've done so far:

-Removed drivers door panel
-Disconnected wire harness to drivers power window motor
-Used a multi-meter to check if drivers window switch is sending power to motor. Tested up and down on switch. Confirmed 12volts up and down. Switch seems to tests ok. Assumed motor is bad
-Ordered new power window motor
-Installed new motor, still not working.
-Disconnected window motor harness, used alligator clips to test window motor with a spare battery. Window moves up and down perfectly and smoothly.
-Again test switch and express down module with meter and harness to motor disconnected, all seems ok. I get up/down voltage, and hear relay clicks from module. Now I'm confused.
-Reconnect wire harness to motor, test, nothing. No clicks from express module, nothing.
-Use meter to test up/down on switch while harness is connected to motor, I get low up/down voltage.

Seems odd. Seems as when you connect the harness to the motor, you get no voltage from switch, and no clicks from express module. I repeat this testing multiple times, and I consistently get 12v up/down from switch, and hear relay clicking from express down module when harness is not connected to motor.

For reference, I test the removed stock drivers motor, and it tests ok.

What could it be? Bad express module, bad switch?

Weird one.

By Jove, I think I've got it!

- Do you have shop manuals, and therefore schematics, yet?
- Did you use that meter to do a continuity check on the Ground wire in the switch-connector?

My bet is that you'll find a broken wire in the "bending zone" going from the door to the dash - and of course the driver's door gets opened waaaaay more often than the passenger's...  It would explain all your symptoms & test results, because they wanted to save a dime on wire and didn't give the RH window switch it's own ground - it piggybacks on the lines coming from the master switch.  When you used a spare battery to test the motor, you provided your own ground.

I asked about keeping the express-down module because you have the door apart at the moment, and you've never had use of your windows...  If you look at my signature info, you'll see that removing that module is one of the many "Factory Annoyances" that I got rid of on my car.  Every other car I've seen with express-down uses a separate detent in the switch so you can push halfway for 'normal' and all the way for express.  These geniuses decided to simply go into express-mode after the switch is held for -get this- "more than 0.3 seconds".  Thus, it basically kicks in every time you want to move the window more than 2 inches.  
EDIT:  I found my original post:  I didn't remove the actual module, just 1 WIRE from its connector. 
(If you're interested, it also contains the procedure to delete the Brake-to-Shift function...)
https://rivperformance.editboard.com/t5428-delete-brake-to-shift-express-down-24hour-power-port?highlight=mirror

Even better, I went into my long-disused Flickr account to add a photo for the ashtray light and found the window schematic!   https://www.flickr.com/photos/24229483@N07/5328570671/in/album-72157618540359112/
It might look blurry when small, but it is sharp when you blow it up to full size.

Finally, depending on what you spent, it is still probably a good idea to keep that motor you bought "on the shelf".  

Mark

Thanks for the tips Mark, let me verify and test grounds/continuity on the switch.

Yes, I have the 99 Service manuals.

To quote Ted Knight in Caddyshack:  
WELLLLLL....  We're WAITinnnngggg!