My power windows didn't work too well over the last 2 months and I finally got down to looking at them. Bottom line was that the problem wasn't the motors or the wiring or the power or indeed not the contacts in the switches themselves. If you look at the switch contacts for the windows, you will notice there is a certain amount of black garbage on them. This is from arcing and there will always be some there. However, if a set of contacts do not have a solid pressure between them when you use a switch, there will be more arcing than normal and the contact garbage will accumulate faster. This will of course result in your windows not working. The switch rocker arms that you toggle for the up/down action on the windows actually send either of 2 plungers downwards to the actuators of each switch contact. These actuators are simple bent tabs that are part of the switch contact itself. In the case of my switches, either the tabs had bent downwards (giving less pressure on the contacts when actuated) or the copper springs (that are part of the contacts) had weakened. I simply bent the copper actuator tabs upwards very slightly and my problem disappeared. When you access the switch contacts, you can clean the contacts but don't do so with an abrasive such as ultra fine sandpaper, emery cloth, rust eraser, etc. This will only accelerate the contact degradation. Some sort of soft tissue paper with a lubricant like alcohol will be better or indeed a contact cleaner.

 

Kinda funny parallel but when Chrysler brought their electronic ignition onto the market in the early seventies, they had a similar problem with it. The distributor cap was not sealed. The rotor arcing to the contacts for the individual plug wires would cause a layer if scale to build up on those contacts. From time to time, the car would just not start. Pop the cap, clean the contacts and you were usually on your way.

 

Pencil eraser works well for cleaning switch contact points.

 

My passenger side would only come down but would not go up so I did your little trick and now it works like a charm. Thanks for the tip.

 

Had the same problem when we bought our 99. Passenger side would not move up/down with passenger door switch.
Removed switch assembly, after several attempts finally solved problem by adding 3 or 4 layers of black electrical tape squares to the contacts building them up. Had a auto down function for a few cycles. It has operated normal now for several weeks.
Plus, I don't need to move window up or down for wife. Priceless !