Replace the rear wiper arm shaft

Check to make sure the wiper arm is firmly attached to the shaft - it sounds like either the wiper came off of the shaft or there is an internal problem with the linkage between the wiper and the motor. Wire would have nothing to do with your problem.

If the wiper fell off of the shaft, there is a bolt or screw that holds the wiper arm on the shaft. The cover over the shaft should be pryed up to expose the screw.
If the arm is firmly attached to the shaft, then you will need to get inside of the assembly to repair.

The wiper arm has a cover on the left end that pops up after gently spreading the two bottom sides apart. That allows the arm to swing out for cleaning the window or replacing the blade.
The wiper blade assembly attaches to the end of the arm . It is pressed in and will pop out with a little force rotating the left side away from the arm. It pops back in with a little push. The arm remains attached to the rotating shaft assembly.
I believe you can then replace just the rubber blade and not the whole blade assembly, if that is your fancy.
Dave

From the wiper motor, the wiper linkage attaches to both wiper arms. If one side is working, then that indicates that your motor is working, and the linkage to at least 1 wiper arm is working.

What's left? The linkage to the other arm, and the connection of the arm to the pivot shaft assembly. Let's find out:

1. Remove the inoperative wiper arm. You will expose the shaft that the wiper arm attaches to. It will have a head on it that looks like a small peanut butter cup, with shallow ridges or splines all the way around it. This can be formed on the end of the shaft, or it can be a separate piece that is removable. If you don't see it, it may have come off with the wiper arm, so look for it to be still embedded in the wiper arm hole. Once you find it, how do those splines look? Are they stripped? If so, they may be rotating within the arm instead of rotating the arm itself.

2. Run the wipers again. Is the shaft rotating? If it is, then the arm and/or splines were the problem, and you need to replace withever component had the stripped splines, whether the arm or that p-nut butter cup splined part. (Or both, if you want to be extra safe and not have to mess with it again for a while.) If you're lucky, it'll be a separate piece that you can replace easily. If not, it'll be formed as part of the wiper linkage, and you'll have to replace the whole linkage. If it's just the arm that's stripped, replace the arm. Easy.

3. If the shaft does NOT rotate with the arm removed, then the linkage is broken, usually at the connection where the wiper shaft connects to the long arm that hooks both wiper shafts together. The bushings are often plastic, and they wear out. If it's plastic, you can get a replacement at the dealer, which will be nice, new plastic to last however long this one did. But if the linkage is metal all the way along, you'll have to do more work than with the easily replaceable plastic connection.

3b. To gain access to the linkage on most vehicles, remove both wiper arms. Next, remove the (usually) black plastic vented piece under & around the wiper shafts. This should allow access to the wiper linkage.

For those who who have neither wiper working and were hoping this would cover it, you're in luck. If neither wiper is working, here's how to test the system:

1. Turn the key to ON.
2. Turn on the wipers.
3. Listen for the sound of the wiper motor. LIsten in the cab, but also in the engine compartment as well. If you hear it but have no wiper movement, your motor is fine and the linkage is the issue.
3b. If you do not hear any motor sounds in the cab or the engine comartment, it's either the motor or the switch (I assume you've checked the fuse already).
4. Check the wiper motor: Does it have a connector for the wires, or just one wire. If it has one wire, remove that wire and check it for voltage with a multi-meter or test-light. If you have a connector, you'll need to know what wire is which. Maybe. Most of the time, the motor is grounded thru the body, so if you remove the bolts and move the motor away from the body, you can check for voltage between the motor and body.
5. If you have no voltage, then it's the switch or wiring, or possibly the resistor, if equipped. If you DO have voltage at the motor, but no motor movement, the motor is bad and must be replaced.

The motor could be bad, but it's likely that the ball joint connections under the hood area under the cowl have become disconnected for the one windshield wiper arm.

The connection of the arm that moves should be checked for being at the correct angle for parking.
Removal & Installation 2000-03 Wiper Motor and Bushing Replacement L4-2.2L (Vin F) & V6-3.0L (Vin R) To Remove:

1. Before servicing the vehicle refer to the precautions at the beginning of this section
2. Remove the wiper arm finish caps
3. Mark both wiper arm positions on the windshield by using a wax pencil or tape
4. Remove or disconnect the following:
   • Wiper arm retaining nuts and washers
   • Wiper arms
   • Weather-strip at rear of hood
     
     
     
     
   • Grill nuts from base of wiper arm shaft
   • Grill
   • Electrical harness connector from the wiper motor
   • Wiper motor retaining bolts
   • Wiper motor assembly from plenum area
   
   
   
   
   
5. If replacing wiper module bushings remove the steel bushing first then the rubber grommet
6. Remove the wiper motor from the transmission assembly

To Install:

1. Install or connect the following:
   • Wiper motor to transmission assembly NOTE: If the wiper module bushings were replaced install the rubber grommet first then the steel bushing.
     
   • Wiper motor to plenum area
   • Wiper motor retaining bolts; torque to 44 lb-in. (5 Nm)
   • Electrical harness connector to the wiper motor
   • Weather-strip at the rear of hood
   • Grill
   • Grill nuts to the base of the wiper arm shaft
2. Install the wiper arm assemblies at the marks made during removal or at the PARK position if a new wiper motor is installed
3. Install the wiper arm retaining washers and nuts; torque to 9 lb-ft. (12 Nm)
4. Install the wiper arm finish caps
5. Verify correct wiper system operation

Good chances are that the motor has gone bad and will need to be replaced. It's a common thing for the rear wipers to stop working,

You can try this first if you got time:
Take the rear hatch apart (screws, spring clips, inner panel screws (12), etc) to get to the wiper motor. Close investigation, the gear box attached to the motor can be opened up. The motor obviously works since it chatters so something else is not working, makes sense. Opened up the gear box, the motor shaft drives a worm drive gear (plastic) that meshes with a gear wheel (plastic) that has an eccentric cam (metal) on the gear wheel that attaches to a metal arm that meshes with another metal gear arm that is attached to a long shaft that passes through the hatch door and terminates with the finely spline end of the shaft (where the wiper attaches to). As the eccentric cam turns around the gear wheel, the metal arm moves back and forth thus creating the wiper effect. Lot of action in a small space,(pretty cool actually). My basic philosophy is that if something can be assembled, it should be able to be DIS-ASSEMBLED (in theory anyway). So fiddling with the thing eventually led me to the conclusion that if you put the wiper nut on the end of the wiper shaft and gently tapped the nut, you could drive the wiper shaft (and its metal gears and arms back out through the metal housing (Oh, forgot to say that the wiper shaft was "rusted" in its sleeve and would not oscillate back and forth). At the end of the shaft (on the outside of the vehicle) there is a metal "washer" that was an incredibly tight fit (this washer holds the shaft from falling into the gear box) so you have to keep tapping on the end of the shaft to eventually drive the shaft past this holding washer. Once you get past the washer the shaft would not pass through its guide sleeve in the metal housing (remember, "rusted" in place, seized). So tapped it out with a Phillips screwdriver acting as a long punch. You can then cleaned the interior sleeve by reaming it with a long circular steel brush (3/8" diameter brush that is designed to clean out push rod holes) and polished the wiper shaft with fine sandpaper, then lubed and reassembled the whole smash making sure the wiper shaft now moves freely in its sleeve. Put it all back together in the vehicle and we'll see if it works. Fingers crossed. This may save you some money if it works.

Front Wiper Motor Removal & Installation

NOTE A new wiper motor assembly comes with the linkage arm installed.

1. Before servicing the vehicle, refer to the Precautions Section.
2. Remove the windshield wiper mounting arm and pivot shaft
   WARNING Do not remove the wiper motor linkage arm from the wiper motor assembly. If the arm is removed, the wiper arms may not park in the correct location.
   NOTE Use a suitable tool to separate the wiper linkage arm from the wiper mounting arm and pivot shaft assembly.
   
3. Remove the 3 bolts and the wiper motor.
   
   
   
   Fig. Wiper motor and linkage
   

To install:

1. Install wiper motor and bolts.
2. Tighten wiper motor bolts to 10 ft. lbs. (13 Nm).
3. Install windshield wiper mounting arm and pivot shaft.
4. Check wiper operation.

Rear Wiper Motor - Removal & Installation

1. Remove the rear pivot arm.
2. Remove the rear wiper motor shaft nut cover
3. Remove the rear wiper motor shaft nut.
4. Open the lift gate window.
5. Remove the rear wiper motor cover trim panel.
6. Disconnect the electrical connector.
7. Remove the 2 rear window wiper motor nuts
8. Remove the rear window wiper motor.
   
   
   Fig. Rear wiper motor view-2008 model shown, other years similar
   

To install:

1. Install rear wiper motor and tighten mounting nuts to 62 inch lbs. (7 Nm).
2. Reconnect the electrical connector.
3. Install wiper motor cover trim panel.
4. Install rear wiper pivot arm tighten nut to 53 inch lbs. (6 Nm).
5. Install shaft nut cover.
   
6. Check wiper operation.

Good luck (remember rated this post).

SECTION 501-16: Wipers and Washers 1999 Town Car Workshop Manual REMOVAL AND INSTALLATION Mounting Arm and Pivot Shaft Removal

1. Disconnect the battery ground cable (14301).

1. Remove the windshield wiper pivot arms (17527).
   1. Remove the nuts (one each side).
   1. Remove the windshield wiper pivot arms.

1. Remove the LH and RH cowl top vent panels.
   1. Remove the hood weatherstrip.
   1. Remove the screws.
   1. Remove the retaining clips.
      • Disconnect the LH and RH washer hoses.

1. Position the windshield wiper mounting arm and pivot shaft (17566) assembly aside.
   1. Remove the nuts.
   1. Remove the bolt.
   1. Position the windshield wiper mounting arm and pivot shaft assembly aside.

1. Remove the windshield wiper mounting arm and pivot shaft assembly.
   1. Disconnect the electrical connector.
   1. Remove the windshield wiper mounting arm and pivot shaft assembly.

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Motor —Windshield Wiper Removal

1. Remove the windshield wiper mounting arm and pivot shaft (17566) assembly; refer to Mounting Arm and Pivot Shaft .

1. Remove the windshield wiper motor (17508).
   1. Remove the output shaft bolt.
   1. Remove the bolts.
   1. Remove the windshield wiper motor.

Remove the rear pivot arm.
Lift the pivot arm to the upright position.
Slide the locking tab out.
Pull up and remove the pivot arm.
Remove the rear wiper motor shaft nut cover.
Remove the rear wiper motor shaft nut.
Remove the rear wiper motor cover.
Remove the rear wiper motor bracket nut.
Remove the bolt and the rear wiper motor.

This is what I Found there was not any Illustration's with it looks Fairly simple, Good luck



FRONT

1. Disconnect linkage assembly from wiper motor shaft.
2. Disconnect electrical connectors from wiper motor.
3. Remove wiper motor attaching bolts, then wiper motor.

REAR

1. Remove wiper blade and arm assembly.
2. Remove access panel on back door.
3. Disconnect linkage assembly from wiper motor shaft.
4. Disconnect electrical connectors from wiper motor.
5. Remove wiper motor attaching bolts, then wiper motor.

Skill
Level Mfg.
Warranty Standard Wiper Motor Labor Replace Front B 0.7 1.0
PLEASE DONT FORGET TO RATE ME Thank You Much

Wiper arms are fitted to a tapered and splined shaft and they can become very tight on the shaft even without the problems of poor maintenance - when servicing a vehicle I always loosen the wiper arm retaining nuts and apply a small amount of chain lube and retighten. Subsequent removal becomes a little easier and the chance of snapping a wiper spindle much reduced.

These days few wiper arms can be removed without using a small gear puller that is sold by tool outlets for the purpose of removing most wiper arms. Recently a colleague needed to manufacture a "special" for a particular car because mine wouldn't fit.

Rear wipers receive no maintenance at all generally and being more exposed to the weather, salt, road dirt, corrosion can be a big factor when removing the arm from the spindle. This is especially so when the rear wiper arm is plastic with a moulded-in ally hub. I have in the past had to resort to carefully cutting and grinding away the arm in order not to risk the spindle or the glass.

I suggest you try a wiper arm puller and a little gentle heat and if that doesn't seem to be working then cutting, grinding or drilling would be the best solution, after protecting the glass with lots of forgiving material...