Any electrical gremlin genius's in the house?
 

Seem to have an interesting one here.weigh in as you see fit...
All electrical works except for drivers window,passenger rear and driver rear.For a while depending on outside temp drivers rear would work fine.No longer.All the motors are working and I have replaced both switches.I Have done continuity testing on drivers side windows and swithches.
Here is the rub....With a window motor(any of them) not connected I get 12 volts at the wire terminals when switch is compressed, but When the terminals are replaced on the motor nothing works.I have tested the motors on a friends car and they all work fine.Is this a "ground" type issue? could it be the ground wire cluster behind the instrument cluster?As it gets warmer, it sure would be nice to be able to open more than one window and the sunroof.A/c is defunct at the moment.thanks in advance for any suggestions.

How do you "compress" a switch?

There should be 12V on the terminals with the switch in the neutral position.

compress,push...just depends on your caffeine level at this hour.With the switch in neutral I am not getting 12v...I only get that when I push(compress....use) the switch.Does this mean the new switches are bad?

I'd need confirmation for the W123, but the W126 sends 12V to the motor on both lines when the switch is in neutral.

Whether it does this is not all that critical. Could be a different switch design. When you get the 12V with the switch depressed, do you get 12V on a single line or both lines? If you get it on only one line, check the other line for ground. In fact, check for 12V using one line as supply and the other line for ground.

If you get 12V, then make the test again by reversing the switch to the opposite position. The 12V and ground should now switch to the opposite leads.

Confirmed.

Sometimes the wires inside the accordion rubber between the doors and columns get mangled over time. Try using a different ground source.

Tks TF.

I will double check this.And run a separate ground to see if that changes anything.

thanks Brian.

I would suggest you use a tail light bulb or something similar to test with. You could have 12v, but not enough current to run the motor.
For example, you could have a wire broken all the way through except for one strand, and the voltmeter will still show 12v, but that one strand of wire will not carry enough current to light a light bulb--or operate your window motor.
As suggested earlier, you could also have a bad ground.

The problem might not be entirely electrical. I removed the below Regulator and Motor from the passanger side rear today. You could run the Window up but not down and when you pressed to go down the motor would not go at all. (What I found was that the Window Regulator Mounting Plate is bent and Regulator Gear Teeth deformed from running on an angle.)
In my case the Motor is not grounded through the through the Chassie. I tested the Motor by swapping the + and - wires from a battery to the 2 wires comming from the Motor (+) to the Green wire and (-) to the Black Wire brought the Window Down;swapping them would raise the window.

Here is the pic showing how warped it is. If I can get the Motor on a good Window Regulator I believe it will work OK.

How do you know that all the motors are working? Have you applied 12V and ground to the connectors at the motors to make the windows go up and down? You need to apply 12V and ground to the connectors to make the window go one way, and reverse the two to make it go the other way.

We'll only go through the front driver's window switch. You should have four connections on the switch. One is a light connection that is connected to the illumination circuit for the dash; one is 12 VDC; and the last two are the connections to the window motor. There are also two brown wires that attach below the safety switch. One is a hard ground, and the other is a switched ground through the safety switch. Pull all three connectors off the driver's side switches. Turn your ignition to position 2 (run). Set your multimeter for VDC and test the 12V feed from the fusebox (red wire). I expect this will be good as you've stated you see 12V at the motors. Now turn on your lights and test the voltage for the light in the switch (blue wire). Turn off the ignition and the lights. Set your multimeter for resistance/continuity. Check for continuity from the connector (only one of the brown wires should be grounded) to ground. Finally, check continuity from the switch to the connections at the motors (green and black wires).

Put the connectors back on the switches. With the ignition switch in position 2 (run) and with window switch in the neutral position, you should be getting 12V at both connections on the motor. When the switch is depressed, one of the connections goes to ground completing the circuit for the motor to operate. If you have your multimeter on both connections at the motor, you should see the voltage change from 0V to +12V to 0V and to -12V as you toggle the switch.

The common thread between the front and the back windows is the ground. The safety switch provides ground to the switches in the rear doors. If you don't have the hard ground, neither the front nor rear window will work.

Good luck. Let us know how you do.

Window motors aren't grounded through the chassis. You have to reverse polarity on the motors to make them go up and down.

Does the motor work that way if you use the switch? If the motor goes one direction but not the other then you have a problem in the switch. In the console put the driver front connector on the passenger front switch and see if that makes the motor go both ways.

Did this by grounding to door, got correct voltage , without(only original wiring) i got nothing. Got good continuity on all wires testable so far.Motor goes up and down when connected to a battery directly.I am going to see if i can locate the attachment point of the ground behind the instr cluster.test it and maybe replace....more to come.been a busy week, have not had much free time.

I would check for the ground at the switch.........first. If you have it (likely), it's a switch problem.