DTC B3875 with RPO L26 or L32
Circuit 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.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B3875 Wiper High Speed Relay Circuit
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 following conditions will cause the DTC to set:
| • | 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 Wiper HI relay.
Conditions for Clearing the DTC
| • | A current DTC B3875 will clear if the short to battery, a short to ground or an open in the wiper high speed relay control circuit is no longer detected by the BCM. |
| • | A history DTC B3875 will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present. |
| • | The BCM receives a clear code command from the scan tool. |
Diagnostic Aids
| • | If the DTC B3875 is a history DTC, the fault may be intermittent. Refer to Testing for Intermittent Conditions and Poor Connections . |
| • | The following conditions may cause an intermittent malfunction or occur: |
| - | An intermittent short to battery, a short to ground or an open in the wiper high speed relay control circuit. |
| - | The Wiper HI relay coil is intermittently shorted to battery. |
| - | The BCM is intermittently shorted to battery, shorted to ground or an open. |
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Wiper/Washer Schematics Connector End View Reference: Master Electrical Component List | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |
2 |
Do the high speed wipers operate? | Go to Testing for Intermittent Conditions and Poor Connections | Go to Step 3 |
3 |
Does the test lamp illuminate? | Go to Step 6 | Go to Step 4 |
4 |
Does the test lamp illuminate? | Go to Step 5 | Go to Step 7 |
5 | Using a test lamp, probe between the wiper high speed relay control circuit and the wiper high relay ground circuit. Does the test lamp illuminate? | Go to Step 9 | Go to Step 8 |
6 | Test for a short to battery positive voltage in the wiper high speed relay control circuit. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 12 | Go to Step 10 |
7 | Test for a poor connection, an open, or a short to ground in the wiper high speed relay control circuit. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 12 | Go to Step 10 |
8 | Test for a poor connection or an open in the ground circuit of the Wiper HI relay. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 12 | Go to Step 11 |
9 | Replace the Wiper HI relay. Refer to Relay Replacement . Did you complete the replacement? | Go to Step 11 | Go to Step 12 |
10 | Replace the body control module (BCM). Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 12 | -- |
11 | Replace the underhood electrical center. Refer to Underhood Electrical Center or Junction Block Replacement . Did you complete the replacement? | Go to Step 12 | -- |
12 |
Does the DTC reset? | Go to Step 2 | System OK |
DTC B3875 with LS4
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 CircuitDiagnostic 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
| • | A current DTC will clear if the short to battery, a short to ground or an open in the wiper high speed relay control circuit is no longer detected by the BCM. |
| • | A history DTC will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present. |
Reference Information
Schematic Reference
Connector End View Reference
Wiper/Washer Connector End Views
Electrical Information Reference
Scan Tool Reference
Circuit/System Testing
- Ignition OFF, disconnect the C2 harness connector at the underhood fuse block.
- Connect a test lamp between the control circuit terminal C1 and battery voltage.
- Command the Wiper High Speed Relay ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
- If all circuits test normal, test or replace the underhood fuse block.
| ⇒ | 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. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for BCM replacement, setup, and programming |
