1999 Pontiac Montana windshield wipers when turning them on always on same speed. When I turn it off it continues for a while to wipe and than stops. Any ideas what's wrong that I can fix it? Thanks.

Question edited for clarity. Part of duplicate question added.
Duplicate question deleted.
Question moved to model category.

This says Pulse Board or the Switch

https://www.google.com/search?q=2004+Pontiac+Montana+front+wipers+won%27t+turn+off

This says it does have a relay... but

https://www.google.com/search?q=2004+Pontiac+Montana+wiper+relay

Nothing shows where it is located.

https://www.google.com/search?q=2004+Pontiac+Montana+wiper+relay+location

Relay here

https://www.autozone.com/electrical-and-lighting/wiper-motor-relay

It may not be releasing, you can test if you can find it!

https://www.autozone.com/electrical-and-lighting/wiper-motor-relay

..

There is an adjustment on the sweep mechanism of wiper.

First you need a wiring diagram, free at http://www.bbbind.com/free_tsb.html Then you need a DVOM - digital volt ohm meter to test the circuit . Then if your not familiar with automotive electrical systems testing ,go on youtube an check out Electric Testing Techniques You Need to Know Also having a factory diagnostic trouble shooting chart would also be usefull . You could just start replacing parts , you mite get lucky . The wiper motor is a high fail part , so is the switch ..You could find the fuse is blown ! But fuse's don't usually blow without a reason . Short to ground , low resistance . ( high current flow) Also knowing how they work and what all is involved in making them work.
The Wiper/Washer System consists of the following components:
• Windshield wiper/washer switch
• Windshield wiper motor module
• Windshield wiper motor
• Windshield washer pump motor
• FRT/WPR/WSHR 25A fuse

Wiper/Washer System Operation
The windshield wiper motor module is part of the windshield wiper motor cover and controls wiper motor operation. The windshield wiper motor is a 2 speed motor and is operated at low speed in all modes except HIGH. The accessory voltage supply circuit to the windshield wiper motor assembly is used to operate the wiper motor in all of the low speed modes. The accessory voltage supply circuit to the windshield wiper/washer switch is used to supply the windshield wiper switch signal circuits and the wiper motor high speed circuit.
When the wiper/washer switch is in the LOW position voltage is supplied through a 24K ohm resistor within the switch to the windshield wiper switch signal 2 circuit, and accessory voltage is supplied to the windshield wiper switch signal 1 circuit. The reduced voltage from the wiper switch signal 2 circuit and accessory voltage from the wiper switch signal 1 circuit causes the wiper motor module to close the wiper motor accessory voltage supply circuit to the wiper motor low speed terminal.
Windshield wiper/washer system MIST operation is identical to LOW operation except that the MIST switch is a press and release type. When the wiper switch is moved to the MIST position and released, low speed wiper motor operation is started and will continue until 1 cycle is complete. If the wiper switch is moved to the MIST position and held, the windshield wiper motor will operate in the LOW mode until the switch is released.

Don't the wipers work in any mode ?
1
Did you review the Wiper/Washer System description and operation and perform the necessary inspections?
YES - Go to Step 2
NO - Go to Symptoms - Wiper/Washer Systems
2
Turn ON the ignition , with the engine OFF.
Operate the windshield wiper/washer switch through all the switch positions.
Does the windshield wiper/washer system operate normally?
YES - Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems
NO - Go to Step 3
3
Turn OFF the ignition.
Disconnect the harness connector of the windshield wiper motor.
Turn the ignition ON, with the engine OFF.
Connect a test lamp from the accessory voltage circuit of the windshield wiper motor to a good ground.
Does the test lamp illuminate?
YES - Go to Step 4
NO - Go to Step 13
4
Connect a test lamp from the accessory voltage circuit to the ground circuit of the windshield wiper motor.
Does the test lamp illuminate?
YES - Go to Step 5
NO - Go to Step 14
5
Connect a test lamp from the signal 2 circuit of the windshield wiper switch to a good ground.
Press the windshield washer switch.
Does the test lamp illuminate?
YES - Go to Step 11
NO - Go to Step 6
Let me know if you make it this far and i will send rest of diagnostic's

You will need to diagnose this with a multi meter....on dark green terminal d at the wiper pulse board, with the wipers on any delay position, you should be reading .0005 Amps and 12 Volts and at the same time on the delay position one click below low(the fastest delay speed) you should be reading .0003Amps and 12V on terminal E gray wire, The purple wire (terminal C) should have 12V on high speed only. The yellow wire (terminal B) should have 12V when the key is on and the black wire (terminal A) should always be grounded....check all of that and we should be able to find your problem.
The Amperage should change on terminal E (the gray wire) with each position on the switch but the change will be very small. i.e. the first speed (longest delay) will read .000017 A, the second setting .00004 A and so on. Check that and let me know...(by the way, amps are checked in series with the connector so unplug it, place one probe in the connector and the other in the motor plug terminal. )

the dash lights is a lose ground or power connection the wipers could be a couple things there is a wiper relay that may be going bad or the wiper motor is going bad could even be both

remove the bolt and unhock the linkage, next turn on the wipers and then turn the wipers off, this will park the motor , you will then postion wipers in the park postion and put linkage on the motor, this will line the wipers up, good day.

GM has a service bulletin on this. You need to replace the crank arm on the motor and the bracket the arm catches to make the arm go down when they park instead of up.

Check the crank arm on the wiper motor. There is a bracket under the crank arm that has a small upward part on it that the bottom of the crank arm is supposed to stop on when its shut off.

Put the wiper in the pulse position and turn the key on. let the wipers sweep one time then turn off the key.

Look under the crank arm to see where it stopped. It should be no farther than 5 mm from the bracket stop. The stop is often times bent or worn out. You will need to replace the crank arm and the bracket in most cases.

• Windshield Wipers Continue to Run When Turn Signal and Windshield Wiper Switch Are Turned OFF

• Damaged turn signal and windshield wiper switch .
• Damaged windshield wiper motor .
• Damaged windshield wiper control module.

Pin Number Circuit Circuit Function 1 57 (BK) Wiper Motor Ground (Park) 2 28 (BK/PK) Wiper Module to Wiper Motor (Park Switch) 3 65 (DG) Wiper Motor Power (Park Feed) 4 61 (Y/R) Wiper Motor Common (RUN) 5 56 (DB/O) Wiper Motor LO 6 58 (W) Wiper Motor HI
Windshield Wiper System The windshield wiper system consists of :

• Windshield wiper motor (17508) (F-type).
• Washer system.
• Windshield wiper control module.
• Turn signal and windshield wiper switch (13K359).

The windshield wiper control module is:

• Located at the instrument panel fuse panel.

The windshield wiper motor is:

• Attached to the cowl top extension (021A36) .
• Connected to windshield wiper mounting arm and pivot shaft (17566) .

The turn signal and windshield wiper switch features a:

• Rotary wiper switch.
• Push type washer actuator.

OFF/Low/High Speed

• Has a two-speed, permanent magnet, three brush electric windshield wiper motor .
• The windshield wiper motor has a brush rigging that permits selection of low or high speed.
• When the turn signal and windshield wiper switch is in the LO position, the common brush and the blue/orange wire brush are used, and the windshield wiper motor operates at low speed.
• When the turn signal and windshield wiper switch is in the HI position, the common brush and the white wire brush are used.
• In HI position, electric current will bypass a portion of the armature winding causing the windshield wiper motor to operate faster.
• When the turn signal and windshield wiper switch is moved to the OFF position, the windshield wiper motor will continue at low speed until the park switch outer contacts open.
• When the park switch contacts open, the windshield wiper motor stops in the park position.

Interval
When the turn signal and windshield wiper switch is in the interval position:

• The wipers make single wipes separated by pauses.
• The rotary switch is on the end of turn signal and windshield wiper switch .
• The length of the pause can be set from approximately 1 to 17 seconds.
• Length of pause decreases as the rotary switch is rotated away from off.
• Length of pause increases as the rotary switch is rotated toward off.

While in the interval wiper mode:

• It is normal to hear a slight click at the beginning of each on/pause cycle. NOTE: When using interval wipers, the first wipe may not occur until after a pause of up to 17 seconds.