Introduction
The B1612 diagnostic trouble code (DTC) indicates an issue with the rear wiper mode select switch circuit. Specifically, it signifies that the vehicle's computer, often the Body Control Module (BCM), has detected an open circuit within the wiring or components associated with the switch that controls the rear wiper's operational modes (e.g., intermittent, low, high, off). This can lead to the rear wiper malfunctioning or not functioning at all, impacting visibility and driving safety, especially in inclement weather. Diagnosing and resolving this issue promptly is crucial for maintaining proper vehicle functionality and ensuring driver safety.
Comprehensive Table: B1612 Wiper Rear Mode Select Switch Circuit Open
| Category | Description | Potential Causes |
|---|---|---|
| Definition | Open circuit in the wiring or components related to the rear wiper mode select switch. | Broken or corroded wiring, loose or disconnected connectors, faulty rear wiper mode select switch, damaged BCM, blown fuse (less common, but possible if the fuse also supplies power to the switch circuit). |
| Symptoms | Rear wiper not working, rear wiper stuck in one mode, intermittent rear wiper operation, no rear wiper operation. | Intermittent wiper function failure, complete rear wiper failure, difficulty selecting wiper modes, no response when changing wiper modes. |
| Affected Components | Rear wiper mode select switch, wiring harness, connectors, Body Control Module (BCM), rear wiper motor. | Rear wiper mode select switch itself, wiring from the switch to the BCM and rear wiper motor, connectors in the wiring harness, the BCM's input circuit for the rear wiper switch, the rear wiper motor. |
| Diagnostic Tools | Multimeter, wiring diagram, scan tool (for reading DTCs and potentially accessing BCM data), circuit tester. | Multimeter to check for continuity and voltage, wiring diagram to trace the circuit, scan tool to confirm the DTC and check related data, circuit tester for quick voltage checks. |
| Troubleshooting Steps | Visual inspection, check for power and ground at the switch, check continuity of the wiring, test the switch, test the BCM. | Inspect wiring for damage or corrosion, verify power and ground at the switch connector, check for open circuits in the wiring, test the switch's functionality with a multimeter, test the BCM's input. |
| Potential Solutions | Repair or replace damaged wiring, clean or replace corroded connectors, replace faulty rear wiper mode select switch, replace faulty BCM (rare), replace blown fuse (if applicable). | Repair broken wires, clean or replace corroded connectors, replace the rear wiper mode select switch, replace the BCM (only after thorough diagnosis), replace the blown fuse. |
| Severity | Moderate - Can significantly impair rear visibility, especially in bad weather. | Reduced rear visibility, safety hazard in rain, snow, or other inclement weather conditions. |
| Related DTCs | Other rear wiper related codes, codes related to the BCM. | Codes indicating problems with the rear wiper motor, BCM communication errors, or other issues within the BCM that might indirectly affect the rear wiper circuit. |
| Location of Switch | Typically located on the steering column stalk or on the dashboard. | Steering column stalk, dashboard. |
| Wiring Color Codes | Refer to the vehicle-specific wiring diagram. Color codes vary by manufacturer and model year. | Vehicle-specific wiring diagram. |
| Connector Types | Refer to the vehicle-specific wiring diagram. Connector types vary by manufacturer and model year. | Vehicle-specific wiring diagram. |
| BCM Function | The BCM receives signals from the rear wiper mode select switch and controls the rear wiper motor accordingly. | The BCM interprets the switch position and activates the appropriate circuit to control the rear wiper motor's operation. |
| Wiper Motor Operation | The rear wiper motor is responsible for physically moving the rear wiper blade. | The rear wiper motor receives power and ground signals from the BCM, which in turn are based on the position of the rear wiper mode select switch. |
Detailed Explanations
Definition: The B1612 code signifies an open circuit in the rear wiper mode select switch circuit. An "open circuit" means that the electrical path is broken, preventing current from flowing. This prevents the signal from the rear wiper mode select switch from reaching the BCM correctly.
Symptoms: Common symptoms include a non-functioning rear wiper, the wiper being stuck in one mode (e.g., always on or always off), intermittent operation, or a complete lack of response when attempting to change wiper modes. These symptoms directly impact the driver's ability to maintain clear rear visibility.
Affected Components: The components directly involved in this circuit include the rear wiper mode select switch itself, the wiring harness connecting the switch to the BCM and the rear wiper motor, the connectors within that harness, and potentially the BCM's input circuit for the rear wiper. While less common, the rear wiper motor could also be indirectly affected.
Diagnostic Tools: A multimeter is essential for checking continuity and voltage within the circuit. A wiring diagram specific to the vehicle model is crucial for tracing the circuit's path. A scan tool is needed to read the DTC and may provide access to BCM data. A circuit tester can be used for quick voltage checks.
Troubleshooting Steps: The troubleshooting process begins with a visual inspection of the wiring and connectors for damage or corrosion. Next, verify the presence of power and ground at the switch connector. Check the continuity of the wiring between the switch, the BCM, and the rear wiper motor. Test the switch's functionality using a multimeter to confirm that it sends the correct signals. Finally, test the BCM's input circuit to ensure it's receiving and processing the signals correctly.
Potential Solutions: The solution depends on the identified cause. This may involve repairing or replacing damaged wiring, cleaning or replacing corroded connectors, replacing the faulty rear wiper mode select switch, or, in rare cases, replacing the faulty BCM. If a fuse has blown, replacing it is necessary, but addressing the underlying cause of the blown fuse is crucial.
Severity: The severity of this issue is considered moderate. While it may not immediately disable the vehicle, it significantly impairs rear visibility, particularly in adverse weather conditions, posing a safety hazard.
Related DTCs: Other DTCs related to the rear wiper system, such as those indicating problems with the rear wiper motor, or codes related to the BCM's communication or internal functions, can provide additional clues to the root cause of the B1612 code.
Location of Switch: The rear wiper mode select switch is typically located on the steering column stalk, often integrated with other controls like the front wipers and turn signals, or less commonly, on the dashboard.
Wiring Color Codes: Wiring color codes are vehicle-specific and essential for identifying the correct wires within the circuit. Always refer to the vehicle's wiring diagram for accurate color codes.
Connector Types: Similar to wiring color codes, connector types vary by manufacturer and model year. The wiring diagram will provide information on the connector types used in the rear wiper circuit.
BCM Function: The BCM plays a central role in controlling the rear wiper. It receives signals from the rear wiper mode select switch, interprets the driver's selection, and then activates the appropriate circuit to control the rear wiper motor's operation.
Wiper Motor Operation: The rear wiper motor is responsible for the physical movement of the rear wiper blade. It receives power and ground signals from the BCM, which are based on the position of the rear wiper mode select switch.
Frequently Asked Questions
What does the B1612 code mean? The B1612 code indicates an open circuit in the rear wiper mode select switch circuit, meaning the electrical connection is broken.
Can I drive with a B1612 code? Yes, you can drive, but reduced rear visibility can be dangerous, especially in bad weather.
What are the most common causes of the B1612 code? Common causes include broken wiring, corroded connectors, or a faulty rear wiper mode select switch.
How do I fix the B1612 code? Troubleshoot the circuit using a multimeter and wiring diagram, then repair or replace the faulty component.
Do I need a mechanic to fix a B1612 code? If you are not comfortable working with electrical systems, it's best to consult a qualified mechanic.
Conclusion
The B1612 DTC, "Wiper Rear Mode Select Switch Circuit Open," signals a break in the electrical circuit controlling the rear wiper's operational modes. Thorough diagnosis, involving visual inspection, circuit testing, and component evaluation, is essential for identifying and rectifying the fault, ensuring proper rear wiper functionality and maintaining safe driving conditions.