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Marc, Technician
Category: Car
Satisfied Customers: 1888
Experience:  33 years exp. automotive repair NYS emisisions repair cert.
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1999 Mercury Grand Marquis: Wiper operates on HIGH only

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Vehicle: 1999 Mercury Grand Marquis. Wiper operates on HIGH only. Wash is OK. I believe the motor is OK. Question: What steps do I take to get to the MULTIFUNCTION SWITH on the steering column, and does the lever for moving the steering wheel have to be removed? Do I have to remove the steering wheel to get to the MULTIFUCTION SWITH?
When you shut the wipers off do they go to the park position?
Customer: replied 10 years ago.
No they fail to go to the park position. Also: No LOW speed and not VARIABLE SPEED. But the HIGH speed works perfectly.

I now have the motor removed. I thought there was control (high, low, park) circuity within the MOTOR UNIT, but now I assume my problem is in the WIPER CONTROL MODULE. This, I assume, is somehow plugged in to the MULTIFUNCTION SWITCH.

Customer Concern

The wipers only work on high, and stop when turned off, but do not park. The fuse was checked and it was okay. The multifunction switch and wiper control module were replaced, same thing. The ground to wiper motor was tested, it was okay. Flow chart testing was started, but could not get to the wiper motor connector without pulling the motor.


Disconnect the wiper control module. Jump power to the Yellow/Red wire in module connector pin 12, and ground to the Dark Blue/Orange wire in module connector pin 8. If the wiper does not run at low speed, verify continuity of both wires from module to motor, and if okay, replace wiper motor.

Potential Causes

Bad wiper motor.
Wiring problem


The wiper control module is under the center of the dash. Normally, you will hear a click from it when the wipers are turned on. The Green wire on module pin 2 should be battery voltage when the key is on and can be used as the power source. Either of the Black wires on module pins 3 and 5 can be used for the ground.

Please post back if youi need more help.

Marc and 3 other Car Specialists are ready to help you
Customer: replied 10 years ago.
Wiper problem: Will NOT run on: PARK, LOW speed, OR VARIABLE SPEED. Will run on HIGH SPEED. WASH WORKS.

I need to know how to isolate the difficulty.

1. Is this a problem within the WIPER CONTROL MODULE, and if so, HOW CAN I REMOVE THE COVER ON THE LOWER HALF OF THIS UNIT. I assume this module is attached to the MULTIFUNCTION SWITCH.

2. Is this a problem within the motor unit? I have removed the motor, but I don't know how to test if a control circuit for LOW and PARK may be defective within the motor.