Did you ever get this figured out?

There are two separate washer pumps. One does both the front windshield and the rear window, and the second is the high pressure for the headlights.

Interesting note: the window motor spins both directions - one way it goes to the front windshield, and the other way it goes to the rear window.

I had this same problem, and the pump motor was failed. I replaced it as a unit. You can pull the plug off the motor and check the voltage if you want to confirm, just have a helper activate the motor. The + and ground will switch, depending on which way it's supposed to be turning. They are different tubes for the fluid though, so a blockage would be the answer if one worked but not the other, but likely not if both are not working.

Hope this helps!

Roger