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Power Window Issues

Having some issues with the power windows. What's happening is the drivers side switches don't work at all, the passenger side does. I know the switches work though, as I tested them on the passenger side and the passenger side on the drivers side, drivers side still don't work, no switch. The door locks do work. All switches worked when on the passenger side.

Now what I have done.

1. Tested switches, they do work.
2. Used a volt meter and checked for power. I checked on the back side of the switch on the pink wire, I get 12.35 ish volts. When I press on the button, the volts drop to 4 ish, nothing else happens. There is power to the motor also.
3. Checked wiring, obviously its good, as I get power. Now I have rewired the whole car, the only OEM wiring is the power windows, mirrors, and power locks. I just ran a new power line to my fuse box. My fuse box is a Ron Francis.

I've been racking my brain for the last week, and I can't figure this out. This is the only major problem I have with the car and it can be driven. I really need the windows to work as I don't have AC at this time. Please help!!! Any advice will be helpful.

Edit: 1990 LX hatchback
 
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If the switches are working and all the electrical checks out; what about mechanical?

The factory nylon rollers are notorious for breaking down after some time has passed.
You can open up the window motor and replace them with steel ball bearings or replace the unit entirely.

Good luck and keep us informed!
 
The switches have power and do work, yes. If it's mechanical with the drivers side, would that affect the passenger window from moving via the drivers door switch? What's a good way to test the window motor?
 
The switches have power and do work, yes. If it's mechanical with the drivers side, would that affect the passenger window from moving via the drivers door switch? What's a good way to test the window motor?
So both sides do not work? IF that's the case then it probably isn't mechanical.
Have you tried using the switch from the passenger side on the driver side? That will at least completely rule out the switches.
If still nothing the trace / test the wires through the door into the passenger compartment. Maybe there is a damaged wire or connector somewhere.
 
So both sides do not work? IF that's the case then it probably isn't mechanical.
Have you tried using the switch from the passenger side on the driver side? That will at least completely rule out the switches.
If still nothing the trace / test the wires through the door into the passenger compartment. Maybe there is a damaged wire or connector somewhere.
Yes I have and they both work on the other door. When I tested the power wire I get power at the switches, but when I press either of them the volts drop. I'll check the connector under the dash that connects the door harness to the harness that goes to the other door.
 
Thanks for the diagrams.

Ok, the motor works as I got it to move up and down with using the battery trick, I could not test the voltage on it as I don't have a voltmeter that size. I did check the volts and amps that's going to the motor when I press the button, it read 4.53 amps, and 12.31 volts. When I tried it before I don't think I had a good enough ground on the multi meter. Is that enough amps? or is there something else I'm not seeing.
 
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