Fix monowiper park position on mercedes c 200 class

It sounds like the wiper parking position relay has failed. You see, when you turn on the wiper a series of relays on the actuator side are energized and cause the wiper motor to turn on and move the mono-wiper through its arc.

When it reaches the maximum extent of its travel, the wiper circuitry then reverses the arms direction and it swings back. This goes on until you turn off the wipers by turning off the ignition key or turning off the power switch.

When you turn off the wipers, the parking circuitry is activated. The central feature of this part of the wiper circuitry is the parking position relay. As the wiper begins to de-energize the parking position relay is activated. The position relay ensures that the wiper returns gently to the same position each time you turn off the wipers.

If the parking position relay weren't there, the wipers would park wherever they stopped on the windshield. However, the relay circuitry charges when you hit the off button and ensures that the wiper arm sweeps down to the same spot each time. If it does not activate, the wiper arm stops as soon as you turn off the power, as noted. This means that the wiper might, one time, stop in the center of the windshield or it might stop all the way to the left of right.

Aside from its complete failure, manufacturers build in telltales that indicate when the circuit is about to go. One of them is the wiper blade's parked position. Normally, the position relay ensures that the de-energized wiper circuit settles gently to the bottom of the windshield, as noted. However, if the position relay is failing most manufacturers have it park some distance from the bottom of the windshield to give you a head's up that the relay is on its way out.

Since the wiper circuits are fairly involved, it is best to leave it to a trained professional to do the work. However, if you feel you have the expertise to do it, your first step is to obtain the serviced manual for your vehicle. The service manual will give you the step-by-step repair procedure.

Since all parts of the wiper circuitry are related be careful, if you are repairing it yourself, that you replace each component according to the instructions as you might damage something else inadvertently.

Before 1995 Ford interval wiper systems mainly consisted of a switch, the motor and the interval governor (also called the wiper control module or 'WCM'). The basic wiper systems just parked the wipers at the end of their travel at the base of the windshield and involved just one park switch.

The more complex systems not only stopped the wipers at the base of the windshield, but would actually recess them below the windshield to park them. This involved using two park switches to turn the wiper motor in a reverse direction. These were installed on the Crown Victoria, Grand Marquis, Town Car, Taurus and Sable.

The wiper switch (named 'Multi-Function Switch' on most models) had a common return or ground circuit and two input or signal circuits to the WCM. Basically, the switch was two modified potentiometers that varied the resistance to ground for the two signal circuits. When the wiper switch was placed in the low or high position, the WCM looked at only one of the circuits- the 'mode input' -and controlled the wiper motor accordingly. If the wiper switch was placed in any of the interval positions, the mode input told the WCM that the switch was in an interval position. The WCM then looked at the second input - the 'delay input' - and used it to determine the amount of delay between wipes.

1) To run the wipers on low or high speed, the WCM provided constant power to the wiper motor on the proper circuit to provide the requested speed. Dual park switch motors
1.1 The first park switch operated basically in the same way as the single switch systems.
1.2 The second park switch worked in the opposite manner- when the wipers were off the park position, the second switch provided a ground for the wiper motor. Power and ground were now provided by the park switches.
1.3 When the wipers needed to park, the polarity of the switches changed, and thus provided reversed voltage to drive the motor in the opposite direction.

2) To run the interval wipers, the WCM applied voltage to the wiper motor only momentarily to get the wipers off the parked position.
3) The electro-mechanical park switch made a circuit between the power feed in and the output to the WCM. Power was provided from the park switch through the WCM and back to the wiper motor.
4) When the wipers reached the park position, the park switch made a circuit between the ground and the output to the WCM, and the motor stopped running. The wiper motor and the wiper switch have remained much the same as the single park switch motors of the past.

The main difference is that the switch has become an input to the GEM instead of the WCM.
1) When the wiper switch is placed in the low or high position, the Run-Park relay is grounded by the GEM to provide constant voltage to the High-Low relay, which then provides voltage to the proper circuit of the wiper motor.
2) High-Low relay is in the low speed position unless grounded by the GEM.
3) The park switch not only feeds the Run-Park relay but is now also an input to the GEM. This tells the GEM when the wipers are in the parked position so it can de-energize the Run-Park relay.
4) When any of the interval positions are selected, the Run-Park relay is momentarily grounded to get the wipers off the parked position
5) The park switch then provides voltage to the other set of contacts in the Run-Park relay.
6) When the GEM de-energizes the Run- Park relay, voltage is still provided from the park switch to the High-Low relay and the wipers complete the stroke.

Click over diagrams for zoom:







Hope this helps.

Take key out of ignition. Remove wiper arm,raise hood to fully upright position, remove cabin air inlet covers. remove wiper assembly, remove motor. Plug new motor in and make sure it is in park position before installing. Good Luck.

Sorry but your description doesn't really make sense - the wipers work, you say, but when switched on they remain in the correct parked position...
Presumably when switched off they park vertically.

It is worth noting the single sweep timer and the screenwash (5 wiper sweeps) influences the self parking. The circuit is quite complicated and it is best not to be involved unless necessary and then a circuit diagram would be invaluable.

It is also important the wiper linkage crank is correctly "timed" to the wiper motor for correct parking.

The wiper motor and integrated gearbox is fairly simple to examine and test but the gearbox also contains the self parking switch which can be examined for wear and cleanliness though testing isn't very practical.

I suggest you begin by removing the wiper motor and examining the condition of the self parking switch inside the gearbox. If it is worn or corroded replace the motor. When refitting connect the wiring and switch on the ignition and then briefly switch on the wiper motor and switch off. The motor should continue for a second or two and then stop.
Switch off the ignition.
Position the wiper blades in the proper parked position and then refit the wiper linkage crank to the motor...

replace the wiper motor, the park position is broken, need to replace complete wiper motor.

was there ice in the cowl, if so the wiper transmission could have been damaged, must remove the cowl cover to inspect.

While the wipers are in the parked state, just loosen off (or remove) the wiper arm from the drive spigot and re-position the driverside wiper arm to the correct position.
Re-tighten arm drive mount and all should be well.

possible nut holding mech. is slightly loose or stripped.

• Windshield Wipers Continue to Run When Turn Signal and Windshield Wiper Switch Are Turned OFF

• Damaged turn signal and windshield wiper switch .
• Damaged windshield wiper motor .
• Damaged windshield wiper control module.

Pin Number Circuit Circuit Function 1 57 (BK) Wiper Motor Ground (Park) 2 28 (BK/PK) Wiper Module to Wiper Motor (Park Switch) 3 65 (DG) Wiper Motor Power (Park Feed) 4 61 (Y/R) Wiper Motor Common (RUN) 5 56 (DB/O) Wiper Motor LO 6 58 (W) Wiper Motor HI
Windshield Wiper System The windshield wiper system consists of :

• Windshield wiper motor (17508) (F-type).
• Washer system.
• Windshield wiper control module.
• Turn signal and windshield wiper switch (13K359).

The windshield wiper control module is:

• Located at the instrument panel fuse panel.

The windshield wiper motor is:

• Attached to the cowl top extension (021A36) .
• Connected to windshield wiper mounting arm and pivot shaft (17566) .

The turn signal and windshield wiper switch features a:

• Rotary wiper switch.
• Push type washer actuator.

OFF/Low/High Speed

• Has a two-speed, permanent magnet, three brush electric windshield wiper motor .
• The windshield wiper motor has a brush rigging that permits selection of low or high speed.
• When the turn signal and windshield wiper switch is in the LO position, the common brush and the blue/orange wire brush are used, and the windshield wiper motor operates at low speed.
• When the turn signal and windshield wiper switch is in the HI position, the common brush and the white wire brush are used.
• In HI position, electric current will bypass a portion of the armature winding causing the windshield wiper motor to operate faster.
• When the turn signal and windshield wiper switch is moved to the OFF position, the windshield wiper motor will continue at low speed until the park switch outer contacts open.
• When the park switch contacts open, the windshield wiper motor stops in the park position.

Interval
When the turn signal and windshield wiper switch is in the interval position:

• The wipers make single wipes separated by pauses.
• The rotary switch is on the end of turn signal and windshield wiper switch .
• The length of the pause can be set from approximately 1 to 17 seconds.
• Length of pause decreases as the rotary switch is rotated away from off.
• Length of pause increases as the rotary switch is rotated toward off.

While in the interval wiper mode:

• It is normal to hear a slight click at the beginning of each on/pause cycle. NOTE: When using interval wipers, the first wipe may not occur until after a pause of up to 17 seconds.
  

This is a common problem with Chevy Venture, Olds Silhouette, and  Pontiac Montana. The mechanical wiper drive and parking cam assembly, if it's not broken, needs adjustment. The spring loaded stop arm should engage the vertical tab on the assembly mounting plate when the wiper motor reverses. See pic. 
I will upload the instructions to fix this problem, if there is interest.