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 |
|---|---|---|---|---|
WPR HI Relay B+ | 1, 2 | 1, 2 | -- | -- |
Windshield Wiper Switch Signal | 1 | 1 | 1 | -- |
Windshield Wiper Switch High Signal | 4 | 2 | 2 | -- |
Windshield Wiper Motor Park Switch Signal | 3 | 3 | -- | -- |
WPR Relay Control | B3715 00 | B3715 00 | B3715 00 | -- |
WPR HI Relay Control | B3875 00 | B3875 00 | B3875 00 | -- |
Windshield Wiper Motor High Speed Control | 2 | 2 | 4 | -- |
Windshield Wiper Motor Low Speed Control | 1 | 1 | 4 | -- |
Windshield Wiper Switch Low Reference | -- | 1, 2 | 1, 2 | -- |
Windshield Wiper Motor Ground | -- | 1, 2, 3 | -- | -- |
WPR Relay Ground | -- | 1 | -- | -- |
1. Delay or Low Speed Wipers Inoperative 2. High Speed Wipers Inoperative 3. Wipers Do Not Park 4. Wipers Always ON | ||||
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 BCM controls the windshield wiper motor through two output controls, controlling two relays which determine the desired wiper speed, high or low.
Conditions for Running the DTC
This DTC can set only when the output is actively being requested by the BCM.
Conditions for Setting the DTC
This DTC sets if the BCM detects a short to ground, open or short to battery voltage on the wiper high speed relay control circuit.
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
Connector End View Reference
Description and Operation
Wiper/Washer System Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Testing
- Ignition OFF, disconnect the WPR HI relay.
- Connect a test lamp between the control circuit terminal 86 and B+.
- 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.
- If all circuits test normal, test or replace the WPR HI relay.
| ⇒ | If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM. |
| ⇒ | 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 BCM. |
Component Testing
Relay Test
- Ignition OFF, disconnect the WPR HI relay.
- Test for 60-200 ohms between terminals 85 and 86.
- Test for infinite resistance between the following terminals:
- Test for less than 2 ohms between terminals 30 and 87A.
- Install a 10A fused jumper wire between relay terminal 85 and 12 volts. Install a jumper wire between relay terminal 86 and ground. Test for less than 2 ohms between terminals 30 and 87.
| ⇒ | If the resistance is not within the specified range, replace the relay. |
| • | 30 and 86 |
| • | 30 and 87 |
| • | 30 and 85 |
| • | 85 and 87 |
| ⇒ | If not the specified value, replace the relay. |
| ⇒ | If greater than the specified range, replace the relay. |
| ⇒ | If greater than the specified range, replace the relay. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for BCM replacement, setup, and programming |
