Both Windshield wipers quit working at the same time

REMOVAL

1. Raise and support the hood.
2. Remove the windshield wiper pivot arms.
3. Remove the cowl top vent panels.

1. Disconnect the windshield wiper mounting arm and pivot shaft.

1. Remove the access cover from the dash panel.
2. Remove the mounting arm and pivot shaft retaining clip.
3. Disconnect the windshield wiper mounting arm and pivot shaft from the windshield wiper motor.

1. Remove the windshield wiper motor.

1. Disconnect the electrical connector.
2. Remove the three bolts.
3. Remove the windshield wiper motor.

INSTALLATION

1. Install the mounting arm and pivot shaft retaining clip on the windshield wiper mounting arm and pivot shaft.

1. Install the windshield wiper motor.

1. Place the windshield wiper motor in the dash panel.
2. Install the three retaining bolts.
3. Reconnect the electrical connector.

1. Reconnect the windshield wiper mounting arm and pivot shaft.

1. Press on the windshield wiper mounting arm and pivot shaft after it is aligned with the windshield wiper motor.
2. Install the access cover in the dash panel.

1. Install the cowl top vent panels.
2. Install the windshield wiper pivot arms.
3. Adjust the windshield wiper pivot arms.

This is technically for the V6 4.2L but I'm sure those Ford E250's have the same setup for windshield wiper motor. Let me know how it goes.

Wiper Motor

Removal & Installation

1. Disconnect the negative battery cable.
2. Disconnect the wiper motor electrical connector.
3. Remove the four mounting bolts securing the motor to the firewall.
4. Using a suitable prybar, carefully separate the wiper motor from the wiper linkage and remove the motor.

To install:

1. Attach the wiper motor ball joint to the wiper linkage.
2. Position the motor on the firewall and secure the motor with the four mounting bolts. Tighten the mounting bolts to 75 ft. lbs. (102 Nm).
3. Connect the electrical connector.
4. Connect the negative battery cable.

the blower motor is located under the windshield wiper assembly. remove wiper arms. remove plastic cover under wiper arms. then must remove wiper motor and wiper transmission assembly. black plastic cover in center of car needs to be removed then the blower motor is under that.

check under the cowl and make shure your wiper arms a conected to the wiper motor.

why do you think the motor still works if the wipers don't move? Can you hear the motor run or can you see a little movement when you turn the switch on?

What happens when you activate the washers?

go to a salvage yard that allows you to remove the parts yourself. Then you can see how the motor and linkage assembly comes out.


don't have 1983 info, but here is 1994:

Section 01-16A: Wiper and Washer System, Ranger/Explorer 1994 Ranger and Explorer Vehicles Workshop Manual
DESCRIPTION AND OPERATION Windshield Wiper System, Ranger/Explorer The windshield wipers are actuated by a permanent magnet, rotary-type electric windshield wiper motor (17504) . The two windshield wiper pivot arms (17526) and windshield wiper blades (17528) are mounted on a pivot shaft, one at each side of the windshield. The windshield wiper mounting arm and pivot shaft (17566) are connected to the motor by windshield wiper adapter and connecting arm clip (17531) . Ranger and Explorer vehicles are equipped with an interval wiper and washer (IWW) system featuring a lever-type turn signal and windshield wiper switch (13K359) mounted on the steering column. The IWW windshield wiper governor (17C476) uses a relay contact to control current to the windshield wiper motor . The governor electronic circuitry controls the contact to supply current to windshield wiper motor . A rear wiper/washer system is available on Explorer vehicles. The rear window wiper system consists of a windshield wiper motor mounted inside the liftgate (40010) , an articulating windshield wiper pivot arm and windshield wiper blade , a windshield wiper/washer switch (17A553) and an inline circuit breaker. The front electric windshield washer system consists of a control switch, integral with the turn signal, a windshield washer reservoir (17618) and windshield wiper motor and the necessary windshield washer hoses (17A605) , windshield washer nozzle jet and brackets (17603) and attaching parts.
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Pivot Shafts and Linkage Removal and Installation
NOTE: The left and right pivot and windshield wiper adapter and connecting arm clip assemblies are serviced separately.

1. Perform Steps 1 through 9 of Windshield Wiper Motor Removal as described in this section.

1. If servicing left windshield wiper adapter and connecting arm clip , remove left windshield wiper mounting arm and pivot shaft and windshield wiper blade assembly.

1. Remove left windshield wiper adapter and connecting arm clip access cover.

1. Remove left pivot nut, lower windshield wiper adapter and connecting arm clip and slide it out through left access opening. For installation, follow removal procedures in reverse order. Tighten nut to 10-13 Nm (7-10 ft-lb). Make sure the clip is fully seated in the windshield wiper adapter and connecting arm clip . Do not try to install clip with windshield wiper adapter and connecting arm clip on motor crank pin.
   

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Windshield Wiper Motor Windshield wiper motor are not serviceable. If worn or damaged, the windshield wiper motor must be replaced as an assembly. Removal

1. Cycle windshield wiper blades until in straight-up position and turn ignition switch OFF.

1. Disconnect battery and wiper motor electrical connector.

1. Remove the right windshield wiper mounting arm and pivot shaft and windshield wiper blade .

1. Disconnect the battery ground cable (14301).

1. Remove the right pivot nut and allow the windshield wiper adapter and connecting arm clip to drop into the cowl top outer panel .

1. Remove the linkage access cover, located on the right side of the dash panel near the windshield wiper motor.

1. Reach through the access cover opening and unsnap the wiper motor clip.

1. Push the clip away from the windshield wiper adapter and connecting arm clip until it clears the nib on the crack pin. Then, push the clip off the windshield wiper adapter and connecting arm clip.

1. Remove the windshield wiper adapter and connecting arm clip from windshield wiper motor crank pin.

1. Remove nut and ground strap.

1. Remove three attaching nuts from windshield wiper motor. Remove the windshield wiper motor .

Installation

1. Position the windshield wiper motor and install the three attaching screws. Tighten to 13.6-19.0 Nm (10-14 ft-lb).

1. Install nut and ground strap.

1. Connect wiper motor electrical connector.

1. Install clip completely onto right windshield wiper adapter and connecting arm clip. Make sure the clip is fully seated. Do not put the windshield wiper adapter and connecting arm clip on the motor crank pin and then try to install the clip.

1. Install the left windshield wiper adapter and connecting arm clip onto the wiper motor crank pin.

1. Install the right windshield wiper adapter and connecting arm clip onto the wiper motor crank pin. Pull the windshield wiper adapter and connecting arm clip onto the crank pin until it snaps into place. The clip is properly installed if the nib is protruding through the center of the clip.

1. Install the right windshield wiper mounting arm and pivot shaft and nut. Tighten the nut to 9.5-12.5 Nm (84-110 in-lb). NOTE: When the battery has been disconnected and reconnected, some abnormal drive symptoms may occur while the powertrain control module (PCM) (12A650) relearns its adaptive strategy. The vehicle may need to be driven 10 miles or more to relearn the strategy.
   

1. Connect the battery ground cable and turn the ignition switch on. Turn turn signal and windshield wiper switch off so windshield wiper motor will park, then turn ignition switch off. Replace right windshield wiper adapter and connecting arm clip access cover.

1. Install the windshield wiper mounting arm and pivot shaft and windshield wiper blade assemblies on the pivot shafts to dimension X. Dimension X is the distance between the centerline of the blade saddle and the top edge of the cowl top outer panel grille. The value of Dimension X for each vehicle is given in the Dimension X chart in the Specifications portion of this section.

1. Test the system.

It's not to difficult, you have to remove the wiper arms, then the wiper cowl,(the panel between the hood and the windshield.) then there is a smaller plastic cover just above the motor. Then you just pop off the link arm from the ball socket and un bolt the motor.

The wipers are parking in the middle because the timing mechanism is off. Once they start doing this it seems to continue to happen so the 1st suggestion is to replace the wiper motor. If U don't want to spend the $ right now it's a pretty easy fix to reset the timing. Park the wipers & remove the wiper arms. Then remove the plastic cowling that covers the wiper motor & the motor assembly. Turn the wiper assembly over without turning the motor. Remove the nut on the arm of the motor. Repostion the arm pointing away from the closet wiper directly inline with the short arm. reassemble.

please rate as fixya if this is what you need. Mounting Arm and Pivot Shaft —Windshield Wiper Removal
NOTE: The windshield wiper pivot arms (17526) must be in the highest position to remove them.

1. Turn the ignition switch (11572) to the on position.

1. Turn the windshield wiper (17500) on.

1. Stop the windshield wiper pivot arms at the highest position by turning the ignition switch off.

1. Remove the windshield wiper pivot arm.
   1. Remove the pivot arm nut cover.
   1. Remove the nut.
   1. Remove the windshield wiper pivot arm.

1. Raise and support the hood (16612).

1. Remove the cowl grille seal.

NOTE: The two cowl grilles overlap at the center. The LH cowl grille must be removed first.

1. Remove the LH cowl grille.
   1. Remove the screw cover.
   1. Remove the screws.
   1. Remove the clips.
   1. Remove the pin-type retainer.
   1. Remove the LH cowl grille.

1. Remove the RH cowl grille.
   1. Remove the screw cover.
   1. Remove the screws.
   1. Remove the clips.
   1. Remove the pin-type retainer.
   1. Remove the RH cowl grille.

1. Remove the mounting arm and pivot shaft.
   1. Disconnect the electrical connector.
   1. Remove the bolts.
   1. Remove the mounting arm and pivot shaft.

there is a bar the goes from your motor to the wiper arms. check that to see if it is attached

I just solved this problem last night with my '05 Impala, and ultimately the solution was what newton5083 stated above.  Yet, it may also be this (I found it online somewhere):
You have bent or broken the "park tab" on the windshield wiper motor bracket. The correct way to fix this is to remove the wiper arms, wiper linkage and wiper motor from the wiper motor bracket, and install a new bracket.
I just bent the tab back into place a couple times for our daughters 2005 Impala but it kept getting bent down again when they didn't take the time to make sure the wipers were not frozen to the windshield, or tried running the wipers to remove heavy snow on the windshield. So yesterday I fabricated a small piece of metal and bolted that to the bracket in the same place the tab stop was.
If someone wants to access this bracket and tab-
1. Use a ½ inch or 13mm socket & ratchet or wrench to remove nuts on wiper arms.
2. They may make a special tool to remove the arms, I used a screwdriver and hammer to tap bottom of the arm to wedge them apart from the spindle.
3. Two small button-looking clips hold the drivers side cowl cover in place under the windshield. These are two-piece clips, pry up the center, than the outer piece.
4. Unclip the washer hose from cowl cover, than pull out plastic cover.
5. There is a smaller plastic cover with on plastic button head holding that cover in place. Gently pry under that clip to remove that cover.
6. Now you can see the wiper trans and bracket. You should see a small tab on that bracket that looks pushed down and bent or possible a square small hole with some torn off metal where the tab broke off.
7. Remove small plastic cover over the wiper transmission and you can see a small spring-loaded arm underneath the wiper transmission assembly.
8. You need to find something to pry that tab back up so when the wipers are running that spring loaded little arm just snaps past the tab running clockwise. It's when you shut off the wipers that the wiper transmission assembly reverses rotation counter clockwise and the small spring loaded arm underneath hits that tab stop, than the wipers will go all the way down and shut off as they should.
Once that tab stop gets bent out of the way the little spring loaded arm has nothing to stop the wiper transmission assembly so it keeps traveling counter clockwise until some other stop shuts the wipers off straight up on the windshield.

There is a revised bracket part # which is supposed to be more durable, GM part #12368639. Here is a copy of the TSB which points out this problem:
Bulletin No.: 05-08-43-003A
Date: March 10, 2005
TECHNICAL
Subject:
Windshield Wipers Park in Up Position (Replace Windshield Wiper Motor Bracket)
Models:
2005 Chevrolet Impala, Monte Carlo
Supercede:
This bulletin is being revised to make a correction to the Parts Information. Please discard Corporate Bulletin Number 05-08-43-003 (Section 08-Body and Accessories).

Condition
Some customers may comment that the windshield wipers park in the out wipe (vertical) position.
Cause
This condition may be caused by a bent park tab on the windshield wiper motor bracket.

Correction
To correct this condition, replace the wiper motor bracket. It will be necessary to transfer the following parts listed below to the new bracket.
^ Wiper transmission
^ Wiper motor crank arm
^ Wiper motor
1. Remove the windshield wiper motor drive system module.
2. Remove the windshield wiper transmission from the windshield wiper motor bracket.
3. Remove the wiper motor crank arm from the windshield wiper motor.
4. Remove the windshield wiper motor from the bracket.
5. Install the windshield wiper motor to the new bracket.
6. Install the wiper motor crank arm to the windshield wiper motor.
7. Install the windshield wiper transmission to the windshield wiper motor bracket.
8. Install the windshield wiper motor drive system module.

A TSB is not a recall, if vehicle is still under warranty the dealer should be repaired for free. If not, you'll have to pay for the repairs.