I know this is old but for anyone else looking for an answer to going from 5 wires down to 3 this is it:
The 2 outer wires are for the backlight so you can see up when the headlights are on. The center 3 wires are for up, power and down. The wire closest to the light bulb (round gray circle on side of switch) is for the down, the center is power in and the other is up.

 

TAKING THE SWITCH APART:

all you need to do is press out the pivot pin. You can see it on the side of the switch (long side). Use something of same dimensions to "press" it out. It not tight at all and easy to do. Then you can take out the internals completely, clean them and put it back together. ( metal rocker, plastic pin with spring inside, outer rocker cover switch. That's it - ya can't screw it up)

I just did this 10 minutes ago and reinstalled, no joke Works great! And it's clean.
Edit: there was a ton of crap in there. I took it apart from the back as well (spread lips and pull out.) and went to town on the case with a dish brush thing and cleaner. Three flushs later it was gtg.

Question: what is the stock arrangement of those center console switches?
UP/DOWN LOCK WIPER
WIPER LOCK UP/DOWN

Anyone know?

 

My 88 and 87 were both arranged, starting from the from driver, as:

up/down, lock, wiper.

 

Well thanks!
It's what I guessed from the wiring lengths.

OCD satisfied!!!