Introduction
The B2185 diagnostic trouble code (DTC) indicates a short to ground in circuit "D" of the rear wiper select switch. This means that the electrical signal from the switch is unintentionally making a direct connection to the vehicle's chassis, creating a low-resistance path that can disrupt the proper operation of the rear wiper system. Understanding the causes, symptoms, and diagnostic procedures associated with this code is crucial for effectively troubleshooting and resolving the issue.
Table: B2185 Rear Wiper Select Switch "D" Short to Ground
| Topic | Description | Potential Solutions |
|---|---|---|
| Definition of B2185 | Rear Wiper Select Switch "D" Circuit Short to Ground. Indicates that the control module has detected an unintended low-resistance path (short) to ground in the designated circuit ("D") of the rear wiper select switch. | N/A (This is a definition, not a problem to solve directly) |
| Common Symptoms | Rear wiper not functioning, rear wiper operating erratically, rear wiper stuck on or off, blown fuses related to the rear wiper system, battery drain (in severe cases), rear wiper motor continuously running. | Inspect and replace blown fuses, diagnose and repair the short to ground. |
| Potential Causes | Damaged wiring harness, chafed wires, corroded connectors, faulty rear wiper select switch, shorted rear wiper motor, water intrusion in the wiring or switch, rodent damage to wiring. | Inspect wiring, repair or replace damaged wiring, clean corroded connectors, replace faulty switch or motor, seal water leaks, repair or replace damaged wiring. |
| Affected Components | Rear wiper select switch, rear wiper motor, wiring harness, connectors, fuses, control module (BCM, GEM, or similar). | Replace faulty switch or motor, repair or replace damaged wiring, clean corroded connectors, replace blown fuses. |
| Diagnostic Tools Required | Multimeter, wiring diagram, circuit tester, scan tool (optional, for reading and clearing codes). | N/A (These are tools, not solutions) |
| Diagnostic Steps | Visual inspection of wiring and connectors, checking for continuity to ground, testing switch functionality, isolating the shorted circuit, using a wiring diagram to trace the circuit. | Repair or replace the damaged component identified during diagnostic steps. |
| Importance of Wiring Diagrams | Essential for understanding circuit layout, identifying components, and tracing wires to pinpoint the location of the short. | Obtain and use the correct wiring diagram for your vehicle's make, model, and year. |
| Safety Precautions | Disconnect the battery before working on the electrical system, avoid working in wet conditions, use insulated tools. | N/A (These are precautions, not solutions) |
| Testing Switch Functionality | Using a multimeter to check for proper resistance or voltage readings at the switch terminals in different switch positions. | Replace the switch if it fails to meet the manufacturer's specifications. |
| Continuity Testing | Using a multimeter in continuity mode to check for a direct connection between the circuit "D" wire and ground. | Isolate and repair the wire that is showing continuity to ground. |
| Isolating the Short | Disconnecting components one by one to narrow down the location of the short. | Repair or replace the component that, when disconnected, causes the short to disappear. |
| Potential for Intermittent Issues | Shorts can be intermittent due to vibration, temperature changes, or movement of the wiring harness. | Carefully inspect the wiring harness, paying attention to areas where it may rub against the vehicle's body or other components. Flex the harness while monitoring for changes in continuity to ground. |
| Role of the Body Control Module (BCM) | The BCM often controls the rear wiper system. A short to ground can damage the BCM. | After fixing the short, check the BCM for proper function. In some cases, the BCM may need to be reprogrammed or replaced. |
| Fuse Protection | Fuses are designed to protect the circuit from overcurrent. Repeatedly blown fuses are a strong indicator of a short to ground. | Do not simply replace the fuse without addressing the underlying short. Replacing the fuse repeatedly will likely result in further damage. |
| Water Intrusion | Water can cause corrosion and shorts in electrical connectors and wiring. | Inspect connectors and wiring for signs of water damage. Clean corroded connectors with electrical contact cleaner. Seal any leaks that may be allowing water to enter the system. |
| Rodent Damage | Rodents can chew on wiring, causing shorts and other electrical problems. | Inspect the wiring harness for signs of rodent damage. Repair or replace any damaged wires. Consider using rodent repellent in the engine compartment to prevent future damage. |
| Circuit "D" Specifics | The specific function of circuit "D" varies depending on the vehicle make and model. It may be related to the wiper speed selection, intermittent function, or park position. | Refer to the vehicle-specific wiring diagram to determine the exact function of circuit "D" and how it relates to the rear wiper system. |
| Impact on Other Systems | In some cases, a short to ground in the rear wiper circuit can affect other electrical systems in the vehicle, particularly if they share a common ground. | Be aware of any other unusual electrical symptoms that may be present. These symptoms can help to narrow down the location of the short. |
| Professional Assistance | If you are not comfortable working on electrical systems, it is best to take the vehicle to a qualified mechanic. | N/A (This is a recommendation, not a solution) |
| Potential for Incorrect Diagnosis | A short to ground can sometimes be misdiagnosed as a faulty wiper motor or switch. | Perform thorough diagnostic testing to confirm the location of the short before replacing any components. Use a multimeter to check for continuity to ground and to test the functionality of the switch and motor. |
| After Repair Verification | After repairing the short, verify that the rear wiper system is functioning properly and that the B2185 code does not return. | Use a scan tool to clear any stored diagnostic trouble codes. Operate the rear wiper in all modes to ensure that it is working correctly. Monitor the system for any signs of malfunction. |
| Importance of Cleanliness | Keep the work area clean and free of debris to prevent contamination of electrical connectors and wiring. | Use electrical contact cleaner to clean connectors and wiring. Avoid using abrasive cleaners or solvents that could damage the components. |
| Grounding Points | Inspect grounding points related to the rear wiper system for corrosion or looseness. | Clean and tighten any corroded or loose grounding points. Poor grounding can cause a variety of electrical problems, including shorts to ground. |
| Component Location | The location of the rear wiper select switch and motor varies depending on the vehicle make and model. | Consult the vehicle's service manual or a wiring diagram to determine the location of these components. |
| Repair Cost Considerations | Repair costs can vary depending on the location of the short and the extent of the damage. | Obtain estimates from multiple repair shops before authorizing any work. Be sure to ask for a detailed breakdown of the costs, including parts and labor. |
Detailed Explanations
Definition of B2185: This DTC specifically points to a short circuit to ground within the "D" circuit of the rear wiper select switch. The vehicle's computer (often a BCM or GEM) monitors the electrical signals from the switch. When it detects an abnormally low resistance path to ground in the "D" circuit, it sets the B2185 code.
Common Symptoms: The most obvious symptom is a malfunctioning rear wiper. This could manifest as the wiper not working at all, operating constantly regardless of the switch position, moving erratically, or being stuck in a particular position. Blown fuses related to the rear wiper circuit are also common. In severe cases, a persistent short can drain the battery.
Potential Causes: The primary culprit is a short circuit. This often stems from damaged wiring where the insulation has worn away, allowing the wire to contact the vehicle's metal chassis. Chafed wires, especially where they pass through body panels or are exposed to the elements, are common. Corroded connectors, a faulty switch, or even a shorted wiper motor can also create this condition. Water intrusion and rodent damage are other frequent causes.
Affected Components: The rear wiper select switch itself is a prime suspect. The rear wiper motor, the wiring harness connecting these components, and the associated connectors are all potentially affected. Fuses protecting the circuit are also involved, and in some cases, the Body Control Module (BCM) or Generic Electronic Module (GEM) could be damaged.
Diagnostic Tools Required: A multimeter is essential for testing continuity, voltage, and resistance. A wiring diagram specific to the vehicle's make, model, and year is critical for understanding the circuit layout. A circuit tester can help quickly identify the presence of voltage in a circuit. A scan tool, while not always necessary, can be useful for reading and clearing codes.
Diagnostic Steps: Start with a thorough visual inspection of the wiring harness and connectors, looking for signs of damage, corrosion, or chafing. Use the multimeter to check for continuity between the "D" circuit wire and ground. Test the functionality of the switch by checking for proper resistance or voltage readings in different positions. Isolate the short by disconnecting components one by one until the continuity to ground disappears. Use the wiring diagram to trace the circuit and identify potential problem areas.
Importance of Wiring Diagrams: A wiring diagram is your roadmap for the electrical system. It shows the location of components, the routing of wires, the color codes of wires, and the connections between components. Without a wiring diagram, it's extremely difficult to trace the circuit and pinpoint the location of the short.
Safety Precautions: Always disconnect the negative battery cable before working on the electrical system to prevent accidental shorts or shocks. Avoid working in wet conditions. Use insulated tools to further minimize the risk of electrical shock.
Testing Switch Functionality: With the wiring diagram in hand, identify the terminals on the rear wiper select switch. Use a multimeter to measure the resistance or voltage between these terminals in different switch positions. Compare your readings to the specifications in the wiring diagram or service manual. If the readings are incorrect, the switch is likely faulty.
Continuity Testing: Set your multimeter to the continuity setting (often indicated by a diode symbol or a beep). Disconnect the "D" circuit wire from the rear wiper select switch. Connect one probe of the multimeter to the disconnected wire and the other probe to a known good ground on the vehicle's chassis. If the multimeter shows continuity (a beep or a low resistance reading), it confirms that the wire is shorted to ground.
Isolating the Short: This involves systematically disconnecting components in the circuit to narrow down the location of the short. For example, disconnect the rear wiper motor. If the continuity to ground disappears, the motor is likely the source of the short. If the short remains, continue disconnecting other components, such as connectors or sections of the wiring harness, until the short is isolated.
Potential for Intermittent Issues: Shorts can be intermittent, meaning they only occur under certain conditions, such as when the vehicle is moving, when the temperature changes, or when the wiring harness is flexed. This makes them more difficult to diagnose. Carefully inspect the wiring harness, paying attention to areas where it may rub against the vehicle's body or other components. Flex the harness while monitoring for changes in continuity to ground.
Role of the Body Control Module (BCM): The BCM often controls the rear wiper system, providing power and ground to the wiper motor based on the position of the rear wiper select switch. A short to ground in the rear wiper circuit can potentially damage the BCM, as the excessive current can overload its internal circuits.
Fuse Protection: Fuses are designed to protect electrical circuits from overcurrent. If a short to ground exists in the rear wiper circuit, the fuse will likely blow. Repeatedly blown fuses are a strong indicator of a short. Never replace a blown fuse with a higher amperage fuse, as this can cause further damage to the electrical system.
Water Intrusion: Water can cause corrosion and shorts in electrical connectors and wiring. Inspect connectors and wiring for signs of water damage, such as rust, green residue, or swollen insulation. Clean corroded connectors with electrical contact cleaner. Seal any leaks that may be allowing water to enter the system. Common areas for water intrusion include the rear hatch seal, the wiring harness grommets, and the rear wiper motor housing.
Rodent Damage: Rodents are notorious for chewing on wiring, which can cause shorts and other electrical problems. Inspect the wiring harness for signs of rodent damage, such as gnawed insulation or exposed wires. Repair or replace any damaged wires. Consider using rodent repellent in the engine compartment to prevent future damage.
Circuit "D" Specifics: The function of circuit "D" is vehicle-specific. It could relate to the wiper speed selection, intermittent function, or park position. Refer to the wiring diagram to understand its exact purpose.
Impact on Other Systems: A short to ground can sometimes affect other electrical systems, especially if they share a common ground. Be aware of any other unusual electrical symptoms that may be present.
Professional Assistance: If you are not comfortable working on electrical systems, it's best to seek professional help.
Potential for Incorrect Diagnosis: Don't assume the wiper motor or switch is bad before thoroughly investigating the short to ground.
After Repair Verification: Verify the repair by ensuring the wiper functions correctly and the code doesn't return.
Importance of Cleanliness: Keep the work area clean to avoid contaminating connectors and wiring.
Grounding Points: Inspect and clean grounding points.
Component Location: Consult the service manual for component locations.
Repair Cost Considerations: Get multiple estimates before authorizing repairs.
Frequently Asked Questions
What does the B2185 code mean? The B2185 code means there's a short to ground in circuit "D" of the rear wiper select switch. This indicates an unintended electrical connection to the vehicle's chassis.
What are the symptoms of a B2185 code? Common symptoms include a non-functioning or erratically operating rear wiper, blown fuses, and potentially a battery drain. The wiper might also be stuck on or off.
What causes a B2185 code? The most common causes are damaged wiring, chafed wires, corroded connectors, a faulty switch, or a shorted wiper motor. Water intrusion and rodent damage can also contribute.
How do I fix a B2185 code? The fix involves diagnosing and repairing the short to ground, which may require replacing damaged wiring, cleaning connectors, or replacing the switch or motor. Use a wiring diagram for guidance.
Can I ignore a B2185 code? No, ignoring a B2185 code can lead to further electrical problems, battery drain, and potentially damage to the BCM. It's important to address the issue promptly.
Conclusion
The B2185 code signals a short to ground in the rear wiper system, requiring careful diagnosis and repair. By systematically checking wiring, connectors, and components, you can locate and fix the short, restoring proper rear wiper function. If you're not comfortable with electrical work, seek professional assistance.