wiper motor or MFS

Did a search and found nothing conclusive so here is what I'd like to know. My wipers will not retract to the down position when on delay, when on low or high speed they operate as designed. How do I tell if I need a MFS or just a wiper motor?

the wiper motor just spins in circles... it doesn't reverse the direction of the wiper, thats all controlled by linkage. Sounds like your issue is whatever controls the wiper motor.

Actually, on the older cars (89 to perhaps 92), the wiper motor controls the wipers' "park" function through some sliding contacts in the end plate of the motor. So, if you have an older model SC, you probably need a new motor. A newer one, the problem probably lies elsewhere.

I had the same problem on my old 1989 and a good used motor fixed the problem completely. The problem was intermittent electrical contact at the sliding contacts I mentioned, because the motor had developed too much end play over time.

Thanks, the car is a 93 and I feel like it's the motor, a similar issue occured on my 89 Mustang years ago and a new motor fixed it. But the Mustang never had a MFS issue so I was just checking.

What do you mean retract on delay? I don't recall my wipers ever parking when on delay. They just hold at the bottom of the stoke.

What I mean is they do not come back down. They hang in the up position and when you turn them off they hang wherever they are on the windshield when turned off. Currently if I want them at the bottom of the windshield I have to turn them off when they are at the bottom near the cowl or else they hang in the up position.

I'm not completely familiar with the later system, but I think a 93 is on the later one. There is a third component in the system called an Interval Governor, and that may be suspect too. It's somewhere under the dash, but I don't know where on a 93.

S_Mazza said:

Actually, on the older cars (89 to perhaps 92), the wiper motor controls the wipers' "park" function through some sliding contacts in the end plate of the motor. So, if you have an older model SC, you probably need a new motor. A newer one, the problem probably lies elsewhere.

I had the same problem on my old 1989 and a good used motor fixed the problem completely. The problem was intermittent electrical contact at the sliding contacts I mentioned, because the motor had developed too much end play over time.

Click to expand...

How hard is it to swap the motor? Mine is having the same symptoms.

It's not too hard to swap, though you can't have too big of hands. You take the wiper arms off, then the cowel off. then unbolt the motor, get the connectors off wiggling behind things.

So you are missing the park operation.

Here is the operation description from alldata and the wiring diagram for a 93:

Description and Operation

PURPOSE
The Interval Wiper/Washer allows the driver to select three wiper speeds: "LO", "HI", or "INT" (Interval). In "INT", wipes can be spaced one second to fifteen seconds apart.

CONSTRUCTION
The Interval Wiper/Washer Control has a momentary Washer Switch, a four-position Wipe Switch, and an Interval Time Adjust knob on the end of the lever.

OPERATION
Washer Operation
Pushing in the knob on the Wiper/Washer Switch sends current from the Wiper Circuit Breaker through the Washer Switch to the Interval Governor and the Washer Pump. If the Wiper Switch is in "LO" or "HI", normal wipe action occurs during washing. If the Wiper Switch is in "OFF" or "INT", Interval Override operates the Electronic Switch and the Governor Relay to apply power to terminal L of the Wiper Motor: The wipers operate in lo speed. When the washer button is released, wipe cycles are provided to dry the windshield. The wipers then return to "OFF" or "INT" operation.

Lo (or Hi) Speed Wiper Operation
When the Wiper switch is in the "LO" (or "HI") position, section A of the Wiper Switch powers the Interval Override input to the Electronic Switch. The Governor Relay is always pulled in. Wiper Motor current then flows through the Wiper Circuit Breaker and the energized contacts of the Governor Relay to terminal L of the Wiper Motor. "HI" speed power is applied to the H terminal of the Wiper Motor through section B of the Wiper Switch.

Interval Wiper Operation
During interval operation, the wipers make single wipes at low speed, separated by a variable length pause.

When first switched to the "INT" position, the Interval Timer momentarily closes the Electronic Switch, energizing the Governor Relay. Current flows to the Wiper Motor terminal L, through the energized contacts of the Governor Relay. Ground is connected to terminal C of the Wiper Motor.

As the Wiper Motor turns, the Wiper Motor Switch changes from the grounded "PARK" position to the hot "RUN" position. Current now flows through the 63 (R) wire, "RUN" contact of the Wiper Motor Switch, and resets the Interval Timer, opening the Electronic Switch. The current path continues through the normally closed Governor Relay contact to terminal L of the Wiper Motor. Wiping continues until one wipe is completed. The Wiper Motor Switch returns to the "PARK" position, power is removed, and the Wiper Motor stops. After a pause (controlled by the variable resistor), the Interval Timer pulls in the Governor Relay to start another wipe.

Braking occurs when the Wiper Motor Switch moves to the "PARK" position. Wiper Motor terminal L is grounded through the "PARK" contact of the Wiper Motor Switch and the deenergized contact of the Governor Relay.