B1616 Wiper Rear Disable Switch Circuit Open

Introduction:

The B1616 diagnostic trouble code (DTC) indicates a problem with the rear wiper disable switch circuit. This switch, typically found on vehicles equipped with a rear wiper, allows the driver to disable the rear wiper function, often when towing a trailer or cargo that might interfere with the wiper's operation. A "Circuit Open" fault means the electrical circuit responsible for communicating the switch's position to the vehicle's computer (Body Control Module - BCM, or similar control module) is broken, preventing the system from functioning correctly. This can lead to the rear wiper operating erratically or not at all, potentially affecting visibility and safety.

Table: B1616 Wiper Rear Disable Switch Circuit Open

Detailed Explanations:

Definition:

The B1616 code signifies that the vehicle's computer, often the Body Control Module (BCM), has detected an open circuit within the rear wiper disable switch circuit. This means there is a break in the electrical path, preventing the switch from communicating its status (enabled or disabled) to the BCM. The BCM relies on this signal to control the operation of the rear wiper.

Symptoms:

Several symptoms can indicate a B1616 code. The most common is a non-functional rear wiper. The wiper may not operate at all, regardless of the switch position. In some cases, the wiper might operate intermittently, stopping and starting unexpectedly. Conversely, the rear wiper could operate continuously, even when the switch is in the "off" position. Finally, the rear wiper disable switch itself might be inoperative, with no effect on the wiper's behavior when toggled.

Possible Causes:

The root cause of a B1616 code can vary. A faulty rear wiper disable switch is a common culprit. The switch's internal contacts may have failed, preventing it from closing the circuit when activated. An open circuit in the wiring harness is another possibility. This could be due to a broken wire, a cut cable, or a loose connection. Corroded or damaged connectors can also interrupt the electrical path. Less frequently, a faulty BCM can cause the code, but this is usually considered a last resort diagnosis after ruling out other possibilities.

Affected Components:

The primary components affected by a B1616 code are the rear wiper disable switch, the wiring harness connecting the switch to the BCM, the connectors within that harness, and the Body Control Module (BCM) or equivalent control module responsible for receiving the switch's signal. While the rear wiper motor itself isn't directly part of the switch circuit, its operation is indirectly affected since the BCM controls the motor based on the switch's input.

Diagnostic Tools:

Proper diagnosis requires a few essential tools. A multimeter is crucial for testing continuity and voltage within the circuit. A wiring diagram specific to the vehicle model is essential for tracing the circuit and identifying component locations. A scan tool can be used to read and clear the B1616 code after repairs. A circuit tester can also be helpful for quickly verifying the presence of voltage at various points in the circuit.

Related DTCs:

The B1616 code may sometimes be accompanied by other DTCs related to the wiper system. These might include other wiper motor related codes (e.g., B1601-B1615, B1617), which could indicate problems with the wiper motor itself or its control circuit. In rare cases, BCM malfunction codes might also be present, suggesting a broader issue with the BCM. Addressing the B1616 code may resolve some of these related issues, but it's crucial to address all present codes for a complete repair.

Severity:

The severity of a B1616 code is generally considered low to moderate. While a malfunctioning rear wiper doesn't directly affect the vehicle's drivability, it can impair visibility in inclement weather, such as rain, snow, or mud. Reduced visibility can compromise safety, making it important to diagnose and repair the issue promptly.

Common Mistakes:

One common mistake is assuming the wiper motor is the problem without checking the switch and wiring. Many people immediately suspect the motor when the wiper doesn't work, overlooking the simpler possibility of a faulty switch or a wiring issue. Another common mistake is neglecting to properly diagnose the circuit before replacing parts. Randomly replacing components without proper testing can be costly and time-consuming, and may not solve the underlying problem.

Location of Components:

The rear wiper disable switch is typically located on the dashboard or center console, within easy reach of the driver. The BCM is usually located under the dashboard or in the center console, often behind a trim panel. The exact location of these components can vary depending on the vehicle make and model, so it's best to refer to the vehicle's service manual for specific information.

Voltage Readings:

To test the switch circuit, use a multimeter to measure voltage at the switch and at the BCM input. With the switch activated (i.e., in the "on" position), voltage should be present at the BCM input, indicating that the switch is properly closing the circuit. With the switch deactivated (i.e., in the "off" position), voltage should be absent, indicating that the circuit is open. These readings can help determine whether the switch is functioning correctly and whether the wiring is intact.

Continuity Testing:

Continuity testing is another essential diagnostic step. With the switch disconnected from the wiring harness, use a multimeter to test continuity across the switch terminals. When the switch is activated, there should be continuity (a low resistance reading), indicating a closed circuit. When the switch is deactivated, there should be no continuity (a high resistance reading), indicating an open circuit. This test confirms the switch's ability to open and close the circuit as intended.

Wiring Harness Inspection:

A thorough visual inspection of the wiring harness is crucial. Visually inspect the wiring harness for any signs of damage, such as cuts, abrasions, or corrosion. Pay close attention to areas where the wiring harness is routed near sharp edges or moving parts, as these are common points of failure. Repair or replace any damaged wiring as needed. Also, ensure that the wiring harness is properly routed and secured to prevent future damage. Use zip ties or wiring clips to keep the harness away from potential hazards.

Frequently Asked Questions:

• What does B1616 mean? It means there's an open circuit in the rear wiper disable switch circuit, preventing proper communication with the vehicle's computer.

• Can I fix B1616 myself? Yes, with basic tools and a wiring diagram, you can diagnose and potentially repair the issue.

• What tools do I need to fix B1616? A multimeter, wiring diagram, scan tool (optional), and basic hand tools are typically needed.

• Is B1616 a serious problem? It's not critical, but a malfunctioning rear wiper can impair visibility and safety in bad weather.

• Will replacing the wiper motor fix B1616? Not necessarily. The problem is with the switch circuit, not the motor itself, unless the motor's wiring is also affected.

Conclusion:

The B1616 code indicates a problem with the rear wiper disable switch circuit, often resulting in a non-functional rear wiper. Thorough diagnosis, starting with the switch and wiring, is crucial to resolving the issue and restoring proper rear wiper operation.