99 LX Windstar window issues

99 LX Windstar - When I received the van the rear driver's side wing didnt work.
2 weeks ago...the passenger side front window quit working.
I replaced the master switch and the same 2 windows dont work.....

So, How do I check these to help narrow down what the problem could be...
Is there a schematic that I can use to test?

Any help would be appreciative.....

Thanks

I had a '96, so my information would not be the best to go by.
I recommend a subscription to alldatadiy, which is a online version of the owner's manual.
You will be able to see the electrical diagrams there.
It might be something as simple as a blown fuse, or worn switch (maybe on passenger side) or something more complicated.
My '96 had an issue with the windows sticking.
One thing that pops into my mind......not an expensive repair or all that difficult.....the slides on the sides of the window glass that are down inside the door can break free, and you have no guide on that side.
It is a couple spot welds that break.
I had that happen on both sides (driver and passenger side) on my '96. The replacement part was not very expensive at the local dealership....and it is held in place by a couple bolts.

If it is more involved.....you can buy the whole regulator assembly and motor/gear assemblies on the rockauto website.

Thanks Wiswind. First, I did not see notification that you responded....dang.
Today I took an ohm meter across the switch and is working, then I took volt meter across several connections on switch and did get 12v. However....I checked the 2 wires that plug into the regulator and nothing.......but again dont know what I should be getting.
I put it all back together and with it quiet, when I try rolling up or down from drivers side I can hear it "energizing" from inside the passenger door. Weird.
No clicks from within the relays inside the control module when trying the passenger window, but I can hear it from the door itself......
I dont want to buy a regulator unless I am sure....it does not look easy to replace.......
Thought I would post my findings....see if anyone has any additional thoughts...
Thanks

To check the switch, the voltage across the switched terminals should go to zero volts if the switch is working, when the switch is engaged. The wiring of window switches is a bit complicated because the window direction (up vs down) is controled by the polarity of the voltage on the motor. The function of the switch is to put 12 volts on one motor terminal while placing ground on the other. The order of these connections is reversed when the window direction is changed. A properly operating electrical circuit will put 12 volts across the two motor terminals when raising the window, and -12 volts across the same two motor terminals when lowering it.

In addition, power for the passenger side window passes through the driver side controls before entering the passenger side control switch. The driver side window power is also controlled external to the switch to support the "one touch" operation of the window.

Thanks tomj76, I will look at that as well.....
Appreciate everyone's help!