GM Service Manual Online
For 1990-2009 cars only

DTC B3875 V8

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC B3875 00:  Wiper High Speed Relay Circuit

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Windshield Wiper Motor Relay Coil Supply Voltage

B3874

2

6

--

Windshield Wiper Switch High Signal

6

4

1

--

Windshield Wiper Switch Low Signal

6

3

1

--

Windshield Wiper Motor Park Switch Signal

5

5

--

--

Windshield Wiper High Speed Relay Control

7

4

B3875

--

Windshield Wiper Motor High Speed Control

2

4

--

--

Windshield Wiper Motor Low Speed Control

2

3

--

--

Wiper PCB Relay Ground

--

2

--

--

Windshield Wiper Motor Ground

--

2

--

--

Windshield Wiper Switch Ground

--

1

--

--

1. Wipers and Washers Inoperative All Modes

2. Wipers Inoperative All Modes and Washers Work

3. Delay or Low Speed Wipers Inoperative

4. High Speed Wipers Inoperative

5. Wipers Do Not Park

6. Wipers Always On

7. Wipers Operate at High Speed in the Low Speed Mode

Circuit/System Description

The body control module (BCM) controls and monitors the state of the wiper high speed relay control circuit. When the windshield wiper switch is placed in to a high speed setting, a signal is applied to the BCM through the windshield wiper switch high signal circuit. The BCM then applies battery positive voltage to the Wiper HI PCB Relay through the wiper high speed relay control circuit. This energizes the relay, allowing battery positive voltage to be applies from the WPR fuse, through the switched contacts of the relay and through the switched contracts of the WIPER HI PCB Relay to the windshield wiper motor. Ground is applied at all times to the coil side of the wiper HI relay and to the windshield wiper motor from G201.

Conditions for Running the DTC

    • The ignition is in the ON position.
    • The ignition voltage is between 9-16 volts.

Conditions for Setting the DTC

    • The BCM detects an short to battery positive voltage in the wiper high speed relay control circuit for over 1 second.
    • The BCM detects an open or a short to ground in the wiper high speed relay control circuit for over 1 second.

Action Taken When the DTC Sets

The BCM will not activate the output.

Conditions for Clearing the DTC

    • The current DTC will become history when the request for the output is removed or when the condition for setting the fault is corrected.
    • The history DTC will clear after 50 consecutive ignition cycles without a fault present.

Reference Information

Schematic Reference

Wiper/Washer Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Wiper/Washer System Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References for Scan Tool Information

Circuit/System Testing

  1. Ignition OFF, disconnect the X2 harness connector at the underhood fuse block.
  2. Connect a test lamp between the control circuit terminal C1 and battery voltage.
  3. Command the Wiper Hi PCB Relay ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
  4. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the body control module.
    If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the body control module.
  5. If all circuits test normal, test or replace the underhood fuse block.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Underhood Electrical Center or Junction Block Replacement
    •  Control Module References for BCM replacement, setup, and programming

DTC B3875 V6

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC B3875 00:  Wiper High Speed Relay Circuit

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Windshield Wiper Motor Relay Coil Supply Voltage

B3874

2

6

--

Windshield Wiper Switch High Signal

6

4

1

--

Windshield Wiper Switch Low Signal

6

3

1

--

Windshield Wiper Motor Park Switch Signal

5

5

--

--

Windshield Wiper High Speed Relay Control

7

4

B3875

--

Windshield Wiper Motor High Speed Control

2

4

--

--

Windshield Wiper Motor Low Speed Control

2

3

--

--

Wiper PCB Relay Ground

--

2

--

--

Windshield Wiper Motor Ground

--

2

--

--

Windshield Wiper Switch Ground

--

1

--

--

1. Wipers and Washers Inoperative All Modes

2. Wipers Inoperative All Modes and Washers Work

3. Delay or Low Speed Wipers Inoperative

4. High Speed Wipers Inoperative

5. Wipers Do Not Park

6. Wipers Always On

7. Wipers Operate at High Speed in the Low Speed Mode

Circuit/System Description

The body control module (BCM) controls and monitors the state of the wiper high speed relay control circuit. When the windshield wiper switch is placed in to a high speed setting, a signal is applied to the BCM through the windshield wiper switch high signal circuit. The BCM then applies battery positive voltage to the Wiper HI relay through the wiper High speed relay control circuit. This energizes the Wiper HI relay, allowing battery positive voltage to be applies from the wiper/ws fuse, through the switched contacts of the wiper relay and through the switched contracts of the Wiper HI relay to the windshield wiper motor. Ground is applied at all times to the coil side of the wiper HI relay and to the windshield wiper motor from G201.

Conditions for Running the DTC

    • The ignition is in the ON position.
    • The ignition voltage is between 9-16 volts.

Conditions for Setting the DTC

    • The BCM detects an short to battery positive voltage in the wiper high speed relay control circuit for over 1 second.
    • The BCM detects an open or a short to ground in the wiper high speed relay control circuit for over 1 second.

Action Taken When the DTC Sets

The BCM will not activate the output.

Conditions for Clearing the DTC

    • The current DTC will become history when the request for the output is removed or when the condition for setting the fault is corrected.
    • The history DTC will clear after 50 consecutive ignition cycles without a fault present.

Reference Information

Schematic Reference

Wiper/Washer Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Wiper/Washer System Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Ignition ON, wiper switch in the HIGH position. Verify the windshield wipers are cycling at the high speed.

Circuit/System Testing

  1. Ignition OFF, disconnect the Wiper HI Relay.
  2. Connect a test lamp between the control circuit terminal  C14 and ground.
  3. Ignition ON, command the high speed wipers ON and OFF using the wiper switch. The test lamp should turn ON and OFF when changing between the commanded states.
  4. If the test lamp is always ON, test the control circuit for a short to Voltage. If the circuit tests normal, replace the BCM.
    If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, test or replace the WIPER HI Relay.

Component Testing

Relay Test

  1. Ignition OFF, disconnect the WIPER HI relay.
  2. Test for 60-200 ohms between terminals  C14 and  A15.
  3. If the resistance is not within the specified range, replace the relay.
  4. Test for infinite resistance between the following terminals:
  5. • C15 and A15
    • C15 and A14
    • C15 and C14
    • C14 and A14
    If not the specified value, replace the relay.
  6. Test for less than 2 ohms between terminals C15 and B14.
  7. If greater than the specified range, replace the relay.
  8. Install a 10A fused jumper wire between relay terminal C14 and 12 volts. Install a jumper wire between relay terminal A15 and ground. Test for less than 2 ohms between terminals C15 and A14.
  9. If greater than the specified range, replace the relay.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Underhood Electrical Center or Junction Block Replacement
    •  Control Module References for BCM replacement, setup, and programming