I know there are 2 write-ups for this on other forums, but one of the pictures doesn't work, and the other I noticed the window regulator looked different than mine (it was from an A4, mine an S4). So here's mine with very complete instructions and multiple pictures. Bit longer, but didn't want to leave out any details.
I am not responsible if you screw up.
What This Does
Gives Driver capability of having all 4 windows to be one touch up AND down of all 4 windows instead of auto up of just the front 2 windows. Also retains auto down for rear passenger windows, as well as now give them auto up of their windows.
*Note for European Owners*
I got a pm from a member in Europe that told me when he did the mod on his Early '99 Eurospec B5 S4, it didn't work, he even lost his auto down function on the side he did it on. I'm adding this to inform those in Europe that this might not potentially work for you. Maybe contact members in your country that have or might know someone who has done this on their B5 S4 and what they did.
Something long and thin to wrap copper around pins. I used my very small pocket knife which had the perfect blade for the job.
First thing you should know, the following steps will apply to both doors exactly. They have the same screws and wires from both. Only thing I will show double of is the regulators, one for each side. Also, just do one door at a time.
1) Remove the following 3 screws (w/ screwdriver), then the handle trim piece (wiggle it out from the bottom with fingers), then the 4th screw (w/screwdriver). Then simply pull firmly up on the door to lift in out of place.
2) Once you've lifted the door panel out of place, there will be wires and cables holding it in place. Unplug the 3 wires (2 at bottom towards speaker area, and one just above that area). Once unplugged, the cable for the door handle is the only thing left. I left in on and just set the door panel aside as the pictures below depict.
3) Unplug connector connected to regulator, remove the 3 bolts (w/ T-30 torx bit), and pull straight out firmly the regulator (cable that brings up and down are not attached to this.)
4) I wrapped the following pins with a strands of copper wire I had in a figure eight (same as original DIY had stated), since I don't have a solder gun and didn't want to make it permanent (in case I messed up). Note the way I hold it so you know which pins are wrapped (the original DIY called these pins 5 and 7).
Driver's Side Regulator
Passenger's Side Regulator
Check post 3 as to why splicing the connector wires won't work.
5) Place regulator back in, reinstall 3 bolts that held it in, reconnect the connector to the regulator, reconnect three wires, and slide door panel back into place (don't forget to put the lock thingy back through the hole). Open the drivers door, put your key in the ignition, turn it so that the electronics in the car work. Using the drivers door window buttons, push down and hold for at least ten (10) seconds to have the window roll down on the door you just worked on, then pull up and hold for at least ten (10) seconds for the window to close. If it doesn't work, try again one more time. (I had to do it twice, don't know why.) Once you see you have one touch down AND up on rear window, screw the remaining screws in place, put back the door trim piece, and move on to the next door.