I just had this same issue happen to my 2000 Camry. The wiper blades worked but the intermittent switch did nothing and they would not return to park. Fun games while it was raining.

The problem is indeed in the motor, but it is just a "leaf spring" as someone earlier mentioned that just snapped.

I soldered mine back together and it works now, lets see how long it lasts. real bummer because the whole motor assembly is fine, i would hate to pay to replace it all.

I took some pictures of my problem.
1) Essentially, just pop the hood and take the two nuts off of either wiper blade arms. They pull right out, you might have to wiggle a little if its been a long time.
2) Remove ALL the clips of the rubber weather strip that goes along the bottom of the two plastic covers (Cowl Louver). The clips hold the cover in place (i broke just about all of mine and i don't know where to get replacements).
3) remove the passenger side cover first, its got some clips that keep the driver side cover from being removed. Slide down and to the right to get it out, there are clips that hold it in place, be careful.
4) repeat for the drivers side cover but slide down and to the left.
5) Now the wiper motor is exposed, you don't need to remove the whole assembly but just the top lid. Remove the three "star" screws and pry the lid off. Its glued on with some tacky sealant, so just slowly pry off.
6) look on the back of the lid and you will see the "leaf spring" or lack there of. Mine snapped and fell onto the gear.

PM if anyone wants higher res pics...this forum has not got with the times and things 600x300 100kb images are good for mechanics *hint hint mods*