Questions and Answers

Mercury Villager Windshield Wipers Q. You have help me before on a problem I had. This one should be easy. I think I already know the answer. I got a 1993 Mercury Villager and the front wipers were acting up. They would work sometime then other times they would not. I bought and installed a new wiper switch, this did not fix it.

Today I bought a wiper motor. Installed it and everything was okay. Checked motor out on low, high, delay, wash cycle. Like I said it was okay. Then my wife takes her car down the street and turns the wipers on.

Now they will not turn off. Turned switch to all settings, then to off, wipers still going. Installed old switch, wiper still going. The only way to get them to stop was to pull the fuse. I believe the wiper motor I just installed is bad.

One can you confirm this?

Two, can you explain how a wiper motor works, how it knows where to park, how the delay works? Wiper problems are always trouble for me to repair.

Thanks,
Mark

A. So you want to know how the Windshield Wiper/Washer System works. Okay, here is more than you ever want to know about the Windshield Washer System.

SYSTEM OPERATION:
With the Ignition Switch in "RUN", voltage is present at the Front Wiper Motor Assembly, the Wiper/Washer Amplifier Assembly and the Front Washer Motor Switch through Fuse 6 (Front Wiper).

WIPER OPERATION Lo/Hi:
With the Interval Wiper/Washer Switch in "LO", pins A and D of the Wiper/Washer receive a resistance signal. The Amplifier Assembly then applies ground to pin C to operate the Front Wiper Motor Assembly at "LO" speed. With the Interval Wiper/Washer Switch in "HI", pins A and D of the Amplifier receive a resistance signal and the Amplifier applies ground at pin E to operate the Front Wiper Motor Assembly at hi speed.

When the Interval Wiper/Washer Switch is moved to "OFF", the Amplifier removes ground from the Front Wiper Motor Assembly. The Motor continues to run since ground is available through its own "RUN" contacts. When the wiper arms reach the end of their strokes, the "RUN" contacts open and the Motor stops.

INTERVAL:
With the Interval Wiper/Washer Switch in "INTERVAL", Pins A and D of the Amplifier receive a resistance signal. The Amplifier then measures the resistance between Pins A & D to determine interval rate. The amplifier then applies voltage at pin C to operate the Motor at Lo speed for proper interval rate.

WASHER OPERATION:
Pushing the end of the combination switch in causes the Washer Switch contacts to close. Pin A of the Amplifier receives a zero ohm signal in reference to pin C. The Amplifier then grounds pin F, causing the Front Washer Motor to run.

Here is a quick symptom chart for you. Since you more or less eliminated the switch, and if you are sure it is not a short circuit, then that leaves just the wiper/washer amplifier.