For the past year or so the driver side rear vent window will not
always open.  Sometimes it works, sometimes not - hitting the motor or
lever mechanism near the window does the trick - again, sometimes.
It's the motor, not the switch.

Thinking it would cost me $100, I went to the dealer.  Yep, they quoted
Cdn$108 for the part "MOTOR, Window Regulator, Left, Quarter Vent
Window Actuator" P/N 04874115.  Thanks - I will keep on hitting it
while trying the advice in another post (99 Caravan Rear window motor).
Happily, JC's advice worked for me.

Access to the motor assembly is easy in the Caravan - pop off the 6x36
inch plastic trim above the rear door inside, then pull on the top of
the plastic trim panel behind the window vent.  Two spring-loaded clips
pop out - that's it, now you can access the motor by removing the two
hex-head bolts and the 2-wire harness clip.

Taking the assembly apart was fairly easy - I just pried with a knife
blade and sharp chisel near the melted "rivets" and managed to pop it
apart without breaking anything.  I think it would be hard to crack the
assembly seriously enough to damage it, it's made of black plastic
(carbon fibre?)  - just make sure to concentrate your prying at the
melted rivet points.  And don't open it too fast afterward, you will
have a few gears all over the place.

The motor slips right out, with the worm gear attached.  It is a
Mabuchi RK-370C motor, you can find a spec sheet on Mabuchi's website
www.mabuchi-motor.co.jp.  I think the actual variant used in the
Caravan is the RK-370CC which has a 15mm shaft.  JC found their motor
at HSC Electronics Supply (www.halted.com) but I couldn't find it
there.  I did find it at www.herbach.com (Herbach and Rademan) p/n
TM02MTR4557 at US$2.50 each.  They have a minimum order of $15 so I
bought two motors and something else.  They shipped the same day -
great service!

I used a flat-bladed screwdriver to carefully slide the wormgear off
(but if you break it, you will be spending $108).  The shaft on the new
motors is only about 9mm (5/16"), but the wormgear seemed to slip back
onto it okay with enough purchase, and friction-fit okay.  I hope it
doesn't break later, because the wormgear itself is longer than the new
shaft by 3 or 4mm.

No soldering required - the motor just plugs into sockets inside the
assembly.  Pop the motor back in, close up the assembly temporarily and
put it back in the car for a test - works great, way faster than the
other one that still works!  If the motor turns the wrong way, I think
you would just take everything back out, flip the motor over, and
re-test in the vehicle.

After everything is good, re-glue the plastic rivets and install the
assembly back in the vehicle.  Pop the panels back in, you're good to
go.

FYI - I did disassemble the old motor and clean the contacts and
brushes.  It was still fairly powerless (but didn't stall anymore) even
outside of the actuator assembly.  I threw it away.