'03 C70 Power Windows problem — intermittent performance

[robotarmy]

I have a 2003 C70 with about 110k. More often than not, when using the "all windows" button, the drivers window stops, but the rest go down all the way. Pressing the button again, the drivers window may go down the rest of the way, or it may take several presses to get it to go down all the way. Sometimes, the system functions just fine (20-30% of the time), with the exception that the drivers window ALWAYS operates more slowly than the other windows. I have not been able to attribute the problem to any other condition, such as weather. It just seems to be completely random. I have removed the switch and "cleaned" the contacts to no avail. Any ideas?
Thanks!

[precopster]

The window frame runs on PVC runners and rollers which require a dousing of plastic grease. Remove the door trim and lubricate the runners at uppermost, half and lowest position of the glass.

The window should begin to operate normally. If not chances are the window motor is beginning to fail.

[robotarmy]

Thanks, precopster. I'll try that.
So let's see if I have this right. Basically, when the widow stops, it "thinks" it has bottomed out because it feels resistance from lack of lubrication?

[timmybdaddyof3]

Exactly, it looks at current draw of the motor... The slower it goes the more resistance it creates in the more current draw there is lube it up it'll move faster and draw less current

[BEJinFbk]

FWIW - Cleaning the contacts shouldn't ever be necessary
on later model C70's. They use a control module to operate
the window motors and the switch never sees any of the high
currents that cause problems on S/V and older C's.

I think you're on the right track cleaning, adjusting and lubing
the driver's window mechanism. Once you've got things taken
apart and the door panel off, you can unplug the window motor
and connect power directly to it to run the motor up and down
while you work on it. I use a small 12 volt gel cell and it works
great.

[timmybdaddyof3]

Yeah, I was not reffering to the window switch, the module that preforms the "auto" function senses the current draw of the motor to determine if the window has reached full travel, lube the rails and the motor will run more effeciently

[robotarmy]

Thanks for all of your input.
I am going to pop the panel off and apply some white grease to those pulleys, like... today!
Hopefully the lack of lubrication hasn't damaged anything.

[robotarmy]

Update:

Thanks for all your help. Pulled the panel off. Discovered the guts not all that accessible. However, managed to get some white grease on one or two pulleys and some of the cable. Once I had the door reassembled, the damned thing was worse than before. Sometimes, it just didn't respond at all to the buttons. I thought I was going to have to spend the grand. Oddly enough, however, the next day the window operated fine and has not malfunctioned since—go figure!
Counting my blessings.

Thanks again!