I an '03 Chevy Venture van whose windshield wipers won't go down.

Might need to replace the switch

The wiper linkage and blades should be in the neutral position, or where they would normally lie when in the "off" position. Hope this helps. Remember to disconnect the battery while replacing electrical components.

the park position is not working on ur circuit board,,need new wiper mot

Does the wiper arms "park" properly when you turn them off or are they different from left to right? In other words, is one sitting higher than the other?
One other thing, I have had a few come in to the shop where the wiper arm was loose where it attached to the spindle. You can check those with a 13mm wrench or socket and make sure they are tight too.

on the wiper harm ...should be a little cap remove-it ,make shure the rignt wiper is at good spot,unscrew the left wiper arm (not shure that its a screw ,could also be a clip under the arm )how ever ,once it is out ,put -it rignt back at is rignt spot...if it is still wrong ...could be the shaft that is worn or someone could ave replaced the harm inside the hood for a wrong one

Check that you have connected the wiper motor correctly - ensure that you havent inadvertently got the polarity wrong!.
Leave the wiper arms off until you get the motor to run and park using the normal wiper on/off switch.
The motor 'park' control switching is normally an integral part of the motor drive gear and is not adjustable.
During your testing, affix a temporary indicator pointer to the end of a wiper arm drive shaft (use masking tape or similar) to prevent damage to motor or levers.

need to change your wiper motor.

You will need to replace the wiper transmission.This is a common problem.

disconnect the negative battery post.
disconnect the harness from the wipper motor, using a 8mm socket, loosen the two crank arm socket screws and lock-washers until the socket releasesfrom the crank arm ball. do not remove the crank arm from the motor.
using a 10mm socket, remove the three motor retaining screws, slide the motor out of the slot in the bracket.
To install make sure the wipers are in the park position, slide the motor into the slot in the bracket. using the 10mm socket, install the three motor retaining screws and tighten to 49-80inch lbs.Using the 8mm socket tighten the two crank arm socket srews and lock washers. connect the harness to the wiper motor.connect the negative battery cable

disconnect the wiper transmission from the motor, then run the motor and turn the motor off with the wiper switch, this will park the motor, re-attach the wiper trans linkage so the wipers are parked/down