I have a 1999 GMC C8500 Windshield wipers only work on high and washer pump wont shut off. I changed motor and module and the switch and it makes no difference. WTF is going on?

If the windshield wipers on your 2002 Corvette won't shut off, it could indicate a problem with the wiper control switch or a malfunction in the wiper motor circuit. Here are some troubleshooting steps you can try:

1. Check the wiper control switch: Ensure that the wiper control switch is in the "Off" position. Sometimes, the switch can get stuck or malfunction, causing the wipers to stay on. Try moving the switch back and forth a few times to see if that resolves the issue.
2. Inspect the wiper motor relay: The wiper motor relay controls the power supply to the wiper motor. If the relay gets stuck or fails, it can cause the wipers to stay on. Locate the wiper motor relay in the fuse box or relay panel and try replacing it with a known working relay of the same type to see if that resolves the issue.
3. Check the wiper motor circuit: The wiper motor circuit may have a short or an electrical problem that is keeping the wipers engaged. Inspect the wiring harness connected to the wiper motor for any signs of damage or loose connections. Use a multimeter to check for continuity and proper voltage in the circuit. If you are not familiar with automotive electrical systems, it is advisable to consult a professional technician or a qualified electrician.
4. Disconnect the battery: As a temporary solution, you can disconnect the negative terminal of the car battery to stop the wipers from running. This will disable other electrical components as well, so it's recommended as a temporary measure until the issue can be properly diagnosed and repaired.

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

..

Wiper/Washer System Components
The Wiper/Washer System consists of the following electrical components:
• Accessory relay
• Heated washer nozzles w/XA7
• WASH NOZ 10A fuse
• Windshield washer fluid level switch
• Windshield washer pump motor
• Windshield wiper motor
• Windshield wiper motor module
• Windshield wiper/washer switch
• Wiper/washer switch 10A fuse
• Wiper motor 30A fuse

Wiper/Washer System Operation
The windshield wiper motor module is part of the windshield wiper motor cover and controls wiper motor operation. The accessory voltage supply circuit to the windshield wiper motor assembly is used to operate the wiper motor in all modes. 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/washer switch is used to supply the windshield wiper switch signal circuits. The windshield wiper switch signal circuit voltage levels to the wiper motor module determine the wiper motor operating mode.
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.

Just replacing parts isn't the way to fix this problem , viewing wiring diagrams too see what all is involved in making the wipers work is . Then using a digital volt ohmmeter to test electrical circuits . Also looking at factory service info. to see how it's suppose to work.
Free wiring diagrams here http://www.bbbind.com/free-tsb/ Enter vehicle info. year , make , model an engine size . Under system click on body & accessories , then under subsystem click on wiper/washer . Click the search button ,then click the blue link. Looking at the wiring diagram i see two fuse's an two relays that are controlled by the BCM - body control module . Also hooking up a scan tool that can read BCM DTC'S - diagnostic trouble codes could be helpful . The wiper switch is a input to the BCM - the BCM will energize the relays to turn on the wipers.

Wiper/Washer System Components
The Wiper/Washer System consists of the following components:
• Windshield wiper/washer switch
• Body control module (BCM)
• Wiper 1 relay
• Wiper 2 relay
• Wiper diode
• Windshield wiper motor
• Windshield washer pump
• Windshield washer nozzles
• Windshield washer solvent container
• Windshield wiper arm and blade assemblies
• Windshield wiper transmission
• WIPER/SW 10A fuse
• WIPER 25A fuse

Wiper/Washer System Description
The body control module (BCM) controls wiper motor low speed operation. The washer pump and high speed operation are controlled directly by the wiper/washer switch. The windshield wiper/washer switch supplies voltage on the signal circuits to the BCM for windshield wiper/washer operation. When WASH, MIST, DELAY, LOW, or HIGH is detected, the BCM energizes the wiper 1 relay by suppling voltage to the relay coil. This allows battery voltage from the WIPER fuse to flow through the relay switched input then through the contacts and out the relay contacts to the wiper 2 relay switch contacts. Since the wiper 2 relay switch contacts are normally closed to the low speed circuit of the windshield wiper motor, the motor will operate at low speed.

DTC B3715 02: Front Wiper Relay Drive Circuit Short to Ground
DTC B3715 05: Front Wiper Relay Drive Circuit Short to Battery or Open

Do you know how to test automotive electrical circuit's using a DVOM - digital volt ohmmeter ? Do you know what a wiring diagram is an how to read one ? Free wiring diagrams here http://www.bbbind.com/free-tsb Enter vehicle info. year , make , model an engine size. Under system click on body & accessories ,then under subsystem click on wiper/ washer's . Click the search button then the blue link.

Windshield Wiper/Washer System Components
The windshield wiper/washer system consists of the following components:
• Windshield wiper/washer switch
• Windshield wiper motor
• Windshield washer pump
• Windshield washer relay
• Outside moisture sensor
• FRT WIPER 25A fuse
• W/S WASH 15A fuse
Windshield Wiper/Washer System Operation
Accessory voltage and ground is supplied to the windshield wiper motor and provides the power for operating the wiper motor and logic power to the wiper motor module. The WASH, MIST, LOW, and DELAY modes are controlled by the windshield wiper/washer switch through a series of internal resistors. The windshield wiper switch supply voltage circuit is a 12-volt reference from the wiper motor module to the wiper/washer switch, and the switch position determines the point on the resistor assembly where the reference voltage is applied. The windshield wiper switch signal 1 circuit supplies the voltage from the resistor assembly to the wiper motor module and the signal voltage determines the operating mode. High speed operation is controlled by the windshield wiper/washer switch through the windshield wiper switch high signal circuit. The windshield wiper switch high signal circuit is supplied 12 volts by the wiper motor module and when the wiper/washer switch is turned to the HIGH position the windshield wiper switch high signal circuit is grounded through the switch ground circuit. The windshield washer pump is controlled through the windshield wash relay. The windshield wash relay coil and switch is supplied battery positive voltage, and during WASH mode the wiper motor module grounds the washer relay control circuit energizing the relay. When the relay is energized battery positive voltage to the switch side of the relay is supplied to the washer pump control circuit.

The is the symptom of a defective wiper switch.

Principles of Operation
The windshield wiper motor receive inputs from the following:

• multifunction switch
• lighting control module (LCM)
• ignition switch
• battery junction box (BJB)
• central junction box (CJB)

The following components are integrated into the windshield wiper motor:

• windshield wiper motor module
• high/low speed relay
• run/park sensor (Hall effect)
• washer pump relay

High Speed Windshield Wipers
High speed is activated when the multifunction switch supplies ground to the windshield wiper motor module inputs. The windshield wiper motor module then supplies ground to the run/park sensor and high/low relay coil, activating the relay with voltage supplied from the ignition switch (RUN/ACC) through the central junction box (CJB). When the windshield wiper motor module receives voltage from the run/park sensor, it removes ground from the run/park sensor, deactivating it. The windshield wiper motor continues to operate from voltage connected through the run/park sensor until the Hall effect senses the magnet in the motor. When the Hall effect senses the magnet in motor the windshield wiper motor returns to the park position, the internal run/park sensor grounds the windshield wiper motor module input and the windshield wiper motor module removes ground from the windshield wiper high/low relay coil, deactivating the high/low relay and windshield wiper motor. The windshield wiper motor module continues to cycle the windshield wipers until the inputs from the multifunction switch are changed from the high speed position.
Low Speed Windshield Wipers
Low speed is activated when the multifunction switch supplies a specific ground to the speed inputs of the windshield wiper motor module. The windshield wiper motor module then supplies ground to only the windshield wiper run/park relay coil, activating it. When the windshield wiper run/park relay is activated, the deactivated windshield high/low relay connects voltage to the windshield wiper motor low input activating the wiper motor. The windshield wiper motor module continues to operate the windshield wiper motor in the same manner as in high speed, but in low speed with the wiper motor connected to the low speed input.
Intermittent Speed Windshield Wipers
The intermittent wiper speed is activated with grounds controlled by the multifunction switch inputs to the windshield wiper motor module. The windshield wiper motor module then activates the windshield wiper run/park relay coil and switches voltage through the windshield wiper high/low relay. The high/low relay remains deactivated, supplying the voltage to the wiper motor low speed input and activates the windshield wiper motor. When the windshield wiper motor module receives the grounded input, the motor continues to operate until Hall effect sensors senses the wiper motors magnet, which turns off the run/park sensor output to the windshield wiper run/park software, deactivating the relay and disconnecting voltage to the wiper motor. The windshield wipers remain parked until the windshield wiper motor module completes a time-out and then repeats the intermittent windshield wiper cycle.
Washer System
The windshield washer is activated by the internal wiper motor module when it receives a ground from the multifunction switch between the washer input. Dependent on the correct ground, the internal wiper motor modules activates the windshield washer relay (internal) by grounding the respective relay coil. When the relay is activated, it connects voltage to the washer pump while the washer level switch provides ground to the washer pump.
Default Mode
The windshield wiper motor defaults to this mode when the run/park sensor does not sense the hall effect magnet inside wiper motor. This can be caused by obstruction of the windshield wipers or a binding linkage. The windshield wiper motor will continue to operate in a high/low speed condition for a period of 60 seconds.

Symptom Chart
Symptom Chart Condition Possible Sources Action

• The wipers are inoperative

• Multifunction switch
• Circuitry
• Ignition switch
• Windshield wiper motor

• Go To Pinpoint Test A .

Do you know how to test automotive electrical circuits using a factory diagnostic test procedure flow chart ?

PINPOINT TEST A: THE WIPERS ARE INOPERATIVE Test Step Result / Action to Take A1 CHECK CIRCUITS 65 (DG) AND 2025 (RD/YE) FOR VOLTAGE

• Key in OFF position.
• Disconnect: Windshield Wiper Motor C125.
• Key in ON position.
• Measure the voltage between windshield wiper C125 pin 5, circuit 2025 (RD/YE), harness side and ground; and between windshield wiper motor C125 pin 8, circuit 65 (DG), harness side and ground.
• Are the voltages greater than 10 volts?

Yes
GO to A2 .

No
REPAIR the circuit(s) in question. TEST the system for normal operation. A2 CHECK CIRCUITS 57 (BK) AND 676 (PK/OG) FOR OPENS

• Key in OFF position.
• Measure the resistance between windshield wiper C125 pin 6, circuit 57 (BK), harness side and ground; and between windshield wiper motor C125 pin 3, circuit 676 (PK/OG), harness side and ground.
• Are the resistances less than 5 ohms?

Yes
GO to A3 .

No
REPAIR the circuit(s) in question. TEST the system for normal operation. A3 CHECK THE MULTIFUNCTION SWITCH

• Disconnect: Multifunction Switch C202b.
• Carry out the multifunction switch component test. Refer to Wiring Diagrams Cell 149 for schematic and connector information.
  
• Does the multifunction switch pass the component test?

Yes
GO to A4 .

No
INSTALL a new multifunction switch. REFER to Section 211-05 . A4 CHECK CIRCUIT 57 (BK) FOR AN OPEN

• Measure the resistance between C202b pin 5, circuit 57 (BK), harness side and ground.
• Is the resistance less than 5 ohms?

Yes
GO to A5 .

No
REPAIR the circuit. TEST the system for normal operation. A5 CHECK CIRCUITS 56 (DB/OG), 58 (WH), 61 (YE/RD), AND 63 (RD) FOR OPENS

• Using the following table, measure the resistance between the multifunction switch C202b harness side and the windshield wiper motor C125 harness side:
  
  Multifunction Switch C202b Windshield Wiper Motor C125 pin 6, circuit 56 (DB/OG) pin 10, circuit 56 (DB/OG) pin 3, circuit 58 (WH) pin 11, circuit 58 (WH) pin 1, circuit 61 (YE/RD) pin 1, circuit 61 (YE/RD) pin 4, circuit 63 (RD) pin 9, circuit 63 (RD)
• Are the resistances less than 5 ohms?

Yes
GO to A6 .

No
REPAIR the circuit(s) in question. TEST the system for normal operation. A6 CHECK FOR CORRECT WIPER MOTOR OPERATION

• Disconnect all wiper motor connectors.
• Check for:
  • corrosion
  • pushed-out pins
• Connect all wiper motor connectors and make sure they seat correctly.
• Operate the system and verify the concern is still present.
• Is the concern still present?

Yes
GO to A7 .

No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. TEST the system for normal operation. A7 CHECK THE WINDSHIELD WIPER MOTOR

• Key in OFF position.
• Disconnect: Windshield Wiper Motor C125.
• Carry out the windshield wiper motor component test as outlined in this section.
• Does the windshield wiper motor pass the component test?

Yes
The system is operating correctly at this time. The concern may have been caused by binding or incorrect pivot arm adjustment. REFER to Windshield Wiper Blade and Pivot Arm Adjustment in this section. TEST the system for normal operation.

No
INSTALL a new windshield wiper motor. REFER to Windshield Wiper Motor in this section.

There are two relay's in the under hood fuse / relay box . Wiper relay an wiper relay 2 . Maybe one is bad . also check fuse #14 25 amp. Wiper fuse.Plus the BCM - body control module has a hand in making the wipers work . Are you familiar with automotive electronic control modules ?
The Wiper/Washer System consists of the following components:
• Windshield wiper/washer switch
• Body control module (BCM)
• Wiper micro relay
• Wiper 2 relay
• Wiper diode
• Windshield wiper motor
• Windshield washer pump
• Windshield washer nozzles
• Windshield washer solvent container
• Windshield wiper arm and blade assemblies
• Windshield wiper transmission
• WIP/WASH 10A fuse
• WIPER 25A fuse

Wiper/Washer System Description
The body control module (BCM) controls wiper motor low speed operation. The washer pump and high speed operation are controlled directly by the wiper/washer switch. The windshield wiper/washer switch supplies voltage on the signal circuits to the BCM for windshield wiper/washer operation. When WASH, MIST, DELAY, LOW, or HIGH is detected, the BCM energizes the wiper micro relay by suppling voltage to the relay coil. This allows battery voltage from the WIPER fuse to flow through the relay switched input then through the contacts and out the relay switched output to the wiper 2 relay switch contacts. Since the wiper 2 relay switch contacts are normally closed to the low speed circuit of the windshield wiper motor, the motor will operate at low speed.

Do you have any speed !

The Wiper/Washer System consists of the following components:
• Windshield wiper/washer switch
• Body control module (BCM)
• Wiper micro relay
• Wiper 2 relay
• Wiper diode
• Windshield wiper motor
• Windshield washer pump
• Windshield washer nozzles
• Windshield washer solvent container
• Windshield wiper arm and blade assemblies
• Windshield wiper transmission
• WIP/WASH 10A fuse
• WIPER 25A fuse

Wiper/Washer System Description
The body control module (BCM) controls wiper motor low speed operation. The washer pump and high speed operation are controlled directly by the wiper/washer switch. The windshield wiper/washer switch supplies voltage on the signal circuits to the BCM for windshield wiper/washer operation. When WASH, MIST, DELAY, LOW, or HIGH is detected, the BCM energizes the wiper micro relay by suppling voltage to the relay coil. This allows battery voltage from the WIPER fuse to flow through the relay switched input then through the contacts and out the relay switched output to the wiper 2 relay switch contacts. Since the wiper 2 relay switch contacts are normally closed to the low speed circuit of the windshield wiper motor, the motor will operate at low speed.

Low Speed Operation
When the wiper switch is in the Low position, voltage is supplied through an internal resistor to the signal circuit. The body control module (BCM) monitors the windshield wiper switch signal 1 circuit, and energizes the wiper micro relay which will operate the windshield wiper motor. The wiper motor will operate at low speed, since the wiper 2 relay is de-energized. Low speed can also be commanded with a scan tool, by commanding Wiper Relay Cmd. ON and OFF. Refer to Scan Tool Output Controls .
High Speed Operation
In the High position, the windshield wiper/washer switch supplies voltage to both the wiper micro relay and wiper 2 relay coils. This energizes both relays and allows battery voltage from the wiper micro relay switched output to the switched input of the wiper 2 relay through its contacts and out the switched output of the wiper 2 relay to the high speed circuit of the windshield wiper motor. The windshield wiper motor will operate at high speed. During high speed wiper motor operation the wiper switch signal circuit is at the low speed signal voltage, and the body control module (BCM) supplies redundant voltage to the wiper relay via the wiper diode.

This info is out of hummer factory service manual !

This is a complex wiper system . Here are all the components involved !
The Wiper/Washer System consists of the following components:
?€¢
Windshield wiper/washer switch

?€¢
Body control module (BCM)

?€¢
Wiper 1 relay

?€¢
Wiper 2 relay

?€¢
Wiper diode

?€¢
Windshield wiper motor

?€¢
Windshield washer pump

?€¢
Windshield washer nozzles

?€¢
Windshield washer solvent container

?€¢
Windshield wiper arm and blade assemblies

?€¢
Windshield wiper transmission

?€¢
WIPER/SW 10A fuse

?€¢
WIPER 25A fuse

Circuit/System Description
The body control module (BCM) controls the wiper motor based on input from the windshield wiper washer switch. The BCM monitors the wiper washer switch through three separate signal circuits and a ground circuit. The windshield wiper switch high signal circuit is used to determine high speed wiper operation, the windshield wiper switch low signal is used to determine low speed, intermittent, and mist operation through the use of a resistor ladder, and windshield washer switch signal circuit is used to determine washer operation. The windshield wiper motor park operation is controlled by the BCM. The BCM recieves an input from the park switch to determine wiper blade position. When the wiper blades are at the bottom of the windshield glass in park position the wiper park switch will open and the circuit will be pulled up to B+ by the BCM. The park signal will be pulled to ground by the wiper motor park switch while the wiper blades are not in the park position.
The BCM controls the windshield wiper motor through two output controls, controlling two relays which determine the desired wiper speed, high or low
Diagnostic Trouble Codes (DTCs)
The body control module (BCM) monitors the voltage on the windshield wiper switch signal 2 circuit for diagnostic purposes. If the circuit is shorted to voltage while the driver is commanded OFF, the BCM will store DTC B3715. If the circuit is shorted to ground while the driver is commanded ON, the BCM will store DTC B3715. Refer to DTC B3715.
It would be best to have a factory scan tool to diagnose this problem . it would make it easier anyway .
It