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 B3922 : Front Wiper Function Select Circuit

### Circuit/System Description

The body control module (BCM) monitors the windshield wiper switch low signal circuit. When the wiper switch is place in the low position, battery voltage is applied through the switch contacts, a series of resistors, and the wiper switch low signal circuit to the BCM. The BCM then applies battery positive voltage to the wiper relay control circuit which energizes the wiper relay. This applies battery voltage from the WPR Fuse through the switch side of the relay to the windshield wiper motor.

### Conditions for Running the DTC

• | The ignition switch is in the ON position.

• | The ignition voltage is between 9-16 volts.

### Conditions for Setting the DTC

The BCM detects a short to ground or a short to battery voltage on the windshield wiper switch low signal circuit.

### Action Taken When the DTC Sets

• | The BCM will not activate the low speed output.

• | The windshield wipers will only operate in the high speed mode.

### Conditions for Clearing the DTC

• | The DTC will clear the current status when the condition for setting the fault is corrected.

• | A history DTC will clear after 50 consecutive ignition cycles without a fault present.

### Circuit/System Verification

Ignition ON, observe the scan tool Windshield Wiper Switch parameter while rotating the wiper switch. The reading should change between Off, Intermittent, and Low.

### Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the turn signal/multifunction switch.
2. Ignition ON, verify the scan tool Windshield Wiper Switch parameter is not Switch Fault.

⇒ | If Switch Fault, test the windshield wiper switch low signal circuit terminal L for a short to ground. If the circuit tests normal, replace the body control module (BCM).

3. If all circuits test normal, test or replace the turn signal/multifunction switch.

### Component Testing

#### Multifunction Switch

1. With the ignition OFF, disconnect the harness connector at the turn signal/multifunction switch.
2. Test the resistance between terminals H and L. Rotate the wiper switch and compare the resistance readings to the values in the Windshield Wiper Switch Values table below for MIST, each DELAY and LOW speed.

⇒ | If the resistance is not within the specified range, replace the turn signal/multifunction switch.

3. Test for infinite resistance between terminals H and K while rotating the wiper switch to MIST, each DELAY and LOW speed positions.

⇒ | If the less than infinite, replace the turn signal/multifunction switch.

4. Test for less than 5 ohms with the wiper switch in the High speed position.

⇒ | If greater than 5 ohms, replace the turn signal/multifunction switch.

5. Test for infinite resistance between terminals H and J while rotating the wiper switch to MIST, each DELAY and LOW speed positions.

⇒ | If less than infinite, replace the turn signal/multifunction switch.

6. Test for less than 5 ohms while pressing the WASHER switch.

⇒ | If greater than 5 ohms, replace the turn signal/multifunction switch.

Important: If the switch tests open in any switch position other than Off, test the wiper/washer switch signal circuits for a short to voltage before replacing the switch.

#### Wiper Switch Values

Switch Position | Resistance
--- | ---
Off | Infinite
Mist | 300-364 ohms
Delay 1 | 3.48K-4.25K ohms
Delay 2 | 2.52K-3.08K ohms
Delay 3 | 1.78K-2.18K ohms
Delay 4 | 1.17K-1.44K ohms
Delay 5 | 697-851 ohms
Low | 300-364 ohms

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Turn Signal Multifunction Switch Replacement

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