Why do the wipers not return to starting position when they are turned off?

Answer 1

The parking pawl probably has a broken spring and is not working correctly. The pawl is a 1.25" long piece of metal external to the motor and is part of the Stack-O-Plates on the output shaft of the motor and to which the wiper push rods are attached. When you turn the wipers to "Off" the motor will reverse direction and the pawl will catch on a stationary tab that is part of the motor/wiper frame. This will hold the wipers in the down position while the motor continues to run and allow the parking Stack-O-Plates-Spring-Wrapped gizmo to do its magic which drags the wiper arms down into the extra low "parked" position. If the tiny spring that holds the pawl in the out position breaks then the pawl will not engage the stationary tab. The wipers will then continue swinging upward through half a swing at which point a cam/switch that is internal to the pulse board (the cover on the motor output gear (three T20 Torx screws to remove) will tell the motor to stop because it thinks the parking Stack-O-Plates gizmo has finished doing its job but instead the wiper arms will be stuck in the "Hello, I'm a dork" raised flag position.

WARNING: Use caution while working around the wiper mechanism. If the key is on and the wiper lever is set to "Intermediate" then the motor can start unexpectedly. If your fingers are down there in the wrong place, the mechanism has more than enough power to break bones and/or peal the skin right off of them. Don't be afraid, just be deliberate and methodical and always be aware if the motor/electronics are energized.

It is very easy to remove the motor/wiper assembly so do not hesitate to do so:

Remove the plastic covers off the wiper arm retaining nuts.

Remove the wiper arm nuts with a 13mm socket.

Twist and pull with your finger tips and finger nails at the base of the small rubber squirt tubing off the hard plastic squirt delivery tubes.

You may have to yard up and down on the wiper arms pretty hard to get them loose from their tapered shafts. Don't be a mindless gorilla but be brave and keep at it. They will come loose.

Remove the cowl cover by pulling or prying out the center of the six retaining push pins. Then lift the cowl cover up then out at a 45 degree angle. You will find the cover is a very tight fit between the right hand wiper shaft and the weatherstrip at the base of the windshield. Be brave and keep pulling and prying until it comes loose.

Reinstalling the cowl cover and getting the rubber weather strip over the cover is the hardest part of the whole job. Use putty knifes (slowly and carefully!) or a very small slender screwdriver. It took me half an hour just to do this part of the job that. ugh.

Remove the 3 bolts holding the wiper assembly.

Disconnect the electrical connector by squeezing the retaining tab that you cant see on the backside of the connector. You have to squeeze real hard.

Lift the wiper assembly out.

Remove the Stack-O-Plates assembly from the motor output shaft (T30 Torx) to access the pawl to put on a spring. I wrapped one and a half loops of spring around one protrusion on the end of the pawl and around one tab of the stationary clip that limits the swing of the pawl to hold it in the "swung out" position. The loop of spring applies very light pressure but that is all it needs. This will all make sense when you are looking at the pawl mechanism. I cut off one and a half loops from a spring like what you would find in a retractable ball point pen but bigger. Use what spring you can find even if it from a ball point pen. When the motor runs in the forward direction the pawl harmlessly swings out of the way as it passes by the stationary tab. Bend the stationary tab in or out as necessary so the pawl engages straight on to it. I will try and post pictures of all this.

Before remounting the whole Stack-O-Plates gizmo assembly you will need to set the motor into the correctly timed position. Plug the motor in, then turn the wipers to "Intermediate". When the motor stops then turn off the ignition switch or quickly disconnect the motor. The motor is now in the correct position. Remount the Stack-O-Plates so there is about 1/4" to 1" space between the pawl and the stationary tab. Tighten down the T30 Torx bolt (blue lock tight recommended) then test the unit to see if the pawl engages to the stationary tab and lets the parking Stack-O-Plates do all its parking gyrations before you remount the whole wiper assembly. When you are all done try not to wear out the wipers by constantly turning them on and off for the next few hours of driving just so you can marvel at your handy work. :O)

Buy the way, if you turn the wipers off and they just wiggle a little bit while the motor goes click-click-click-click trying to do its parking thing then you need to alter (slightly) the relationship between the cam/switch arm inside the pulse module (again, the cover on the motor output gear, three T20 Torx screws to remove). There are two switch/contact arms in the center of the pulse board. The one closest to the board that engages the plastic cam mounted to the board is the one you want to change slightly. The other free floating arm is driven by the cam on the big motor output gear and is the contact to let the electronics know the output gear has rotated half a turn and the wipers are now parked. I bent the one arm closest to the pulse board away from its cam just slightly so that only about 3/4 of the "hook" on the end of the arm (you will know what I mean when you look at it) is hitting the ramp on the cam (the cam spins clockwise). Verify that the electrical contact actually opens a bit when the arm is riding on the high part of the cam. You may have to adjust and verify a number of times to find that sweet spot where it runs reliably. It took me half an hour of fiddling. O_0