For 1990-2009 cars

### 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 B3873 00: Front Washer Relay Circuit

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Windshield Washer Switch Signal | 2 | 1 | 1 | --
Windshield Washer Fluid Pump Control | 1 | 1 | 2 | --
Windshield Washer Relay Control | 2 | 1 | B3873 00 | --
Windshield Washer Switch Low Reference | -- | 1 | -- | --
Windshield Washer Fluid Pump Ground | -- | 1 | -- | --
1. Washer Inoperative 2. Washers Always ON

### Circuit/System Description

The Body Control Module (BCM) controls the washer pump motor based on an input from the windshield wiper/washer switch. The BCM monitors the washer switch through the windshield washer switch signal circuit. When the wash switch is closed, ground is supplied to the windshield washer switch signal circuit. When this is seen, the BCM will apply ground to the WSW relay control circuit and command the windshield washer fluid pump and the low speed wipers on.

### Conditions for Running the DTC

A washer request is present.

### Conditions for Setting the DTC

A short to voltage is detected in the windshield WSW relay control circuit.

### Action Taken When the DTC Sets

Washer operation is suspended.

### Conditions for Clearing the DTC

• | A current DTC will clear when the condition for setting the fault is no longer seen.

• | A history DTC will clear after 100 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 WSW Relay.
2. Connect a test lamp between the control circuit terminal 85 and the B+ terminal circuit 86.
3. Command the washers ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

⇒ | 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.

4. If all circuits test normal, test or replace the WSW Relay.

### Component Testing

1. Ignition OFF, disconnect the WSW Relay.
2. Test for 60-200 ohms between terminals 85 and 86.

⇒ | If the resistance is not within the specified range, replace the relay.

3. Test for infinite resistance between the following terminals:

• | 30 and 86

• | 30 and 87

• | 30 and 85

• | 85 and 87

⇒ | If not the specified value, replace the relay.

4. Test for less than 2 ohms between terminals 30 and 87A.

⇒ | If greater than the specified range, replace the relay.

5. 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 greater than the specified range, replace the WSW relay.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Control Module References for BCM replacement, setup, and programming

• | Relay Replacement