rear wipers 2002

I have the standard rear intermittent wiper, trying to fix it. I took it apart and it has a circuit board with several transistors and a small microcontroller chip...Does anyone understand the principle of operation? There seems to be only one wire to control the entire unit, and I want to try to test it. There are 3 wires, ground, +12 and this blue control wire.

Anyone know the details of this?

Thanks, Don