B2179 Front Wiper Select Switch "A" Short to Ground

Introduction:

The B2179 diagnostic trouble code (DTC) indicates a fault within the front wiper system of a vehicle, specifically a short to ground in the circuit associated with wiper select switch "A." This malfunction can lead to inoperative or erratic wiper behavior, compromising driver visibility and safety, especially in inclement weather. Understanding the causes, symptoms, and diagnostic procedures for this code is crucial for effective troubleshooting and repair.

Comprehensive Breakdown of B2179

Topic	Description	Common Causes
Definition	The B2179 code signifies that the vehicle's Powertrain Control Module (PCM) or Body Control Module (BCM) has detected an unwanted electrical connection (short) between the "A" circuit of the front wiper select switch and the vehicle's ground. This incorrect path for electrical current prevents the switch from functioning as intended and can affect the overall wiper system operation.	Damaged wiring harness, Faulty wiper select switch, Water intrusion, Improper grounding, PCM/BCM failure
Symptoms	The most common symptoms include non-functional wipers, wipers operating at incorrect speeds, wipers that won't turn off, wipers that only work intermittently, or wipers that don't respond to switch inputs. In some cases, other electrical issues may arise due to the short circuit affecting other systems.	Non-functional wipers, Incorrect wiper speeds, Wipers that won't turn off, Intermittent wiper operation
Possible Causes	Several factors can trigger a B2179 code. These include chafed or damaged wiring in the wiper switch circuit, a malfunctioning wiper select switch itself (internal short), corrosion or water intrusion affecting electrical connections, improper grounding of the wiper system components, or, in rare cases, a failure within the PCM or BCM. The "A" circuit specifically refers to a particular wire or signal path within the wiper switch circuitry, often related to a specific speed or function.	Damaged wiring, Faulty wiper switch, Corrosion, Water intrusion, Poor grounding, PCM/BCM failure
Diagnostic Steps	The diagnostic process involves a systematic approach. First, a visual inspection of the wiper switch, wiring harness, and connectors for any signs of damage or corrosion is essential. Next, using a multimeter, the technician will test the continuity of the "A" circuit to ground, confirming the short circuit. Further testing involves isolating the switch and wiring to pinpoint the exact location of the short. If the wiring and switch are deemed good, the PCM/BCM may require further testing or replacement.	Visual inspection, Continuity testing, Circuit isolation, PCM/BCM testing
Wiring Diagram Relevance	A wiring diagram specific to the vehicle's make and model is indispensable for diagnosing a B2179 code. The diagram shows the exact wiring layout of the wiper system, including the location of the wiper select switch, the "A" circuit, ground connections, and the PCM/BCM. It allows the technician to trace the circuit, identify potential short locations, and perform accurate voltage and continuity tests. Without a wiring diagram, troubleshooting becomes significantly more difficult.	Identifying circuit layout, Tracing the "A" circuit, Locating ground connections, Performing tests
Wiper Motor Function	While the B2179 code directly relates to the wiper select switch, the wiper motor's functionality can be indirectly affected. The short circuit in the switch circuit can prevent the motor from receiving the correct signals, leading to improper operation or complete failure. Therefore, the motor should be tested to ensure it is functioning correctly after addressing the short in the switch circuit.	Affected by incorrect signals, Improper operation or failure, Requires testing after switch circuit repair
Component Location	The wiper select switch is typically located on the steering column or dashboard, easily accessible to the driver. The wiring harness runs from the switch to the wiper motor and eventually to the PCM/BCM. Grounding points for the wiper system are usually found on the vehicle's chassis near the wiper motor or under the dashboard. The specific location of these components varies depending on the vehicle's make and model.	Steering column/dashboard (switch), Wiring harness routing, Chassis (grounding points)
Repair Procedures	Repairing a B2179 code typically involves addressing the short circuit in the "A" circuit. This may require repairing or replacing damaged wiring, replacing the wiper select switch if it's faulty, cleaning corroded connections, or improving grounding. In severe cases, if the PCM or BCM is damaged, it may need to be reprogrammed or replaced. After the repair, the code should be cleared and the wiper system tested to ensure proper functionality.	Wiring repair/replacement, Switch replacement, Connection cleaning, Grounding improvement, PCM/BCM repair
Related DTCs	Other DTCs related to the wiper system, such as codes for the wiper motor circuit or other wiper switch circuits, may accompany the B2179 code. Addressing all related codes is important for a complete and effective repair. Ignoring related codes can lead to recurring problems or misdiagnosis. Examples include codes related to the wiper motor relay or position sensor.	Wiper motor circuit codes, Wiper switch circuit codes, Wiper motor relay codes, Wiper position sensor codes
Tools Required	Diagnosing and repairing a B2179 code typically requires a multimeter, a scan tool capable of reading and clearing DTCs, a wiring diagram specific to the vehicle, wire strippers, crimpers, and possibly soldering equipment. A visual inspection often requires a flashlight and possibly a mirror to access hard-to-reach areas. Safety glasses and gloves are recommended for personal protection.	Multimeter, Scan tool, Wiring diagram, Wire strippers/crimpers, Soldering equipment, Flashlight

Detailed Explanations

Definition: The B2179 code indicates an unintended electrical connection between a specific circuit ("A") of the front wiper select switch and the vehicle's ground. This short circuit disrupts the normal operation of the wiper system.

Symptoms: Common symptoms include wipers that don't work at all, operate at the wrong speed, won't turn off, work intermittently, or don't respond to the driver's input from the switch. Other electrical issues can sometimes arise.

Possible Causes: The most frequent causes are damaged wiring, a faulty wiper switch, corrosion, water intrusion into electrical connectors, poor grounding, or, less commonly, a failure within the vehicle's computer (PCM/BCM).

Diagnostic Steps: Diagnosis starts with a visual inspection of the switch, wiring, and connectors. A multimeter is then used to confirm the short circuit. The switch and wiring are isolated to pinpoint the location of the fault. If these components are good, the PCM/BCM is investigated.

Wiring Diagram Relevance: A wiring diagram is essential for tracing the "A" circuit, identifying ground connections, and performing accurate tests. It shows the layout of the entire wiper system, enabling efficient troubleshooting.

Wiper Motor Function: While the code focuses on the switch, the wiper motor's operation can be affected by the short circuit, leading to improper function or failure. Testing the motor after repairing the switch circuit is crucial.

Component Location: The wiper switch is typically on the steering column or dashboard. Wiring runs from the switch to the motor and the PCM/BCM. Grounding points are usually on the chassis near the motor or under the dashboard.

Repair Procedures: Repairing the code involves fixing the short circuit. This could mean repairing or replacing wiring, replacing the switch, cleaning corroded connections, or improving grounding. In rare cases, the PCM/BCM may need repair or replacement.

Related DTCs: Other codes related to the wiper system might be present alongside B2179. Addressing all related codes is important for a complete and lasting repair.

Tools Required: A multimeter, scan tool, wiring diagram, wire strippers/crimpers, and possibly soldering equipment are generally needed. A flashlight and safety gear are also recommended.

Frequently Asked Questions

What does the B2179 code mean? It signifies a short to ground in the "A" circuit of the front wiper select switch, causing wiper malfunction.
Can I drive with a B2179 code? Driving with this code is not recommended, especially in inclement weather, as it can impair visibility due to wiper malfunction.
Is B2179 an easy fix? The difficulty of the repair depends on the cause. A simple wiring repair is easier than replacing the PCM/BCM.
How do I find the short to ground? Use a multimeter to perform a continuity test between the "A" circuit and ground, then visually inspect the wiring for damage.
Will a new wiper switch fix the B2179 code? A new switch will only fix the code if the existing switch is the source of the short circuit.

Conclusion

The B2179 code indicates a short to ground in the front wiper select switch circuit, leading to wiper malfunction. A systematic diagnostic approach, utilizing a wiring diagram and appropriate tools, is crucial for identifying and repairing the fault, ensuring safe and reliable wiper operation.