Often, it’s the switches. Always check switches before attacking motors, locks or anything else.

The switches must work freely (read “snappy”) for the windows to work properly. They can get stuck (intermittently) in no-man’s land.

They have two basic positions – on and off. For instance, if the passenger side switch gets stuck (it’ll feel sluggish or mushy, not snappy) between the on and  off position,  whether in up or down direction, and since the driver’s side window switch for passenger side’s sent power destined for the passenger side window motor must pass through the passenger side switch, it won’t ever get to the window motor since the passenger side switch is sticking in no-mans land.

Solution – new switch.

No. Remove switch, spray (flood it) with WD-40 and give it some exercise – just operate a bunch of  times. Likely it’ll start moving like it should – with the snappiness of your headlight switch or the switch in your house for the bathroom light.

Now you’ve rejuvenated the lost volatiles in the grease in the switch applied by Volkswagen over a couple decades ago.