B1712 - Mirror Switch R Input Shorted to Ground

Introduction:

The diagnostic trouble code (DTC) B1712, "Mirror Switch R Input Shorted to Ground," indicates an electrical fault within the vehicle's mirror control system. Specifically, it signifies that the signal wire for the "R" (Right) input of the mirror switch is experiencing an unintended connection to ground, disrupting the intended electrical circuit and preventing the proper functioning of the right-side mirror adjustment. This issue can stem from various factors, including wiring damage, a faulty switch, or problems within the body control module (BCM).

Table: B1712 - Mirror Switch R Input Shorted to Ground

Detailed Explanations:

Definition: The B1712 code specifically refers to a situation where the electrical signal intended to control the right-side mirror adjustment is inadvertently connected to the vehicle's ground. This short circuit disrupts the intended flow of electricity, preventing the mirror motor from receiving the correct signals and thus hindering proper adjustment.

Symptoms: The most obvious symptom is the inability to adjust the right-side mirror. However, the mirror might also move erratically or be stuck in a single position. In some cases, the entire mirror switch might become inoperative. Less common symptoms include other electrical issues, a parasitic battery drain (if the short circuit is drawing excessive current), and the illumination of the Check Engine Light (CEL). The driver's side mirror could also be affected if it shares a circuit with the passenger side.

Possible Causes:

• Damaged Wiring Harness: The wiring leading to the mirror switch and the mirror motor itself is susceptible to damage. This can include frayed, cut, or pinched wires caused by wear and tear, exposure to the elements, or accidental damage during repairs.

• Faulty Mirror Switch: The mirror switch itself can develop an internal short circuit. This is a common failure point, especially in older vehicles.

• Corroded or Loose Connectors: Corrosion on the electrical connectors can create a path to ground. Loose connectors can also lead to intermittent shorts.

• Problems with the Body Control Module (BCM): Although less common, a malfunction within the BCM, which controls various electrical functions including the mirror adjustment, can cause this code.

• Water Intrusion: Water entering the wiring harness or the mirror switch can create a short circuit.

• Improperly Installed Aftermarket Accessories: Incorrectly installed accessories, such as aftermarket stereos or alarms, can sometimes interfere with the vehicle's electrical system and cause shorts.

• Rodent Damage: Rodents can chew on wiring harnesses, causing damage and creating short circuits.

• Previous Accident Damage: Past accidents can damage wiring, leading to shorts that may not become apparent until later.

• Incorrect Wiring Repairs: Improperly performed wiring repairs can introduce shorts into the system.

• Defective Ground Connection: A poor ground connection near the mirror switch can cause erratic behavior and trigger the B1712 code.

Troubleshooting Steps:

• Visual Inspection: Begin by visually inspecting the wiring harness and connectors associated with the mirror switch and the right-side mirror motor. Look for any signs of damage, such as frayed wires, cuts, corrosion, or loose connections. Pay close attention to areas where the wiring passes through body panels or near moving parts.

• Testing the Mirror Switch: Use a multimeter to test the mirror switch's functionality. Consult a wiring diagram for your specific vehicle model to identify the correct pins to test. Check for continuity between the "R" input and ground when the switch is not activated. There should be no continuity. If there is, the switch is likely faulty.

• Checking for Continuity and Shorts in the Wiring: Disconnect the mirror switch and the mirror motor. Use a multimeter to check for continuity between the "R" input wire and ground. There should be no continuity. If there is, there's a short to ground in the wiring. Also, check for continuity between the "R" input wire and the other wires in the harness to rule out shorts between wires.

• Inspecting the BCM: Visually inspect the BCM for any signs of damage, such as corrosion or burnt components. If you suspect a problem with the BCM, you might need to have it tested by a qualified technician.

• Using a Multimeter: A multimeter is essential for diagnosing electrical problems. Use it to check for voltage and resistance in the circuit. Compare your readings to the specifications in the vehicle's service manual.

• Scanning for Other DTCs: Use an OBD-II scanner to check for other DTCs that might be related to the B1712 code. Other codes can provide valuable clues about the underlying problem.

• Consulting a Wiring Diagram: A wiring diagram is crucial for understanding the electrical circuit for the mirror adjustment system. It will show you the location of all the components, the wiring connections, and the ground points.

• Checking Ground Connections: Ensure that all ground connections associated with the mirror switch and the mirror motor are clean and secure. A poor ground connection can cause a variety of electrical problems.

• Testing the Mirror Motor Directly: Apply power and ground directly to the mirror motor to see if it functions properly. If the motor works when powered directly, the problem is likely in the wiring or the switch.

• Component Testing with a Scan Tool: Some advanced scan tools have component testing capabilities that can help you diagnose problems with the mirror switch and the BCM.

• Verify Power and Ground Supply to Mirror Switch: Use a multimeter to confirm that the mirror switch is receiving proper power and ground. Without adequate power and ground, the switch will not function correctly.

• Isolate the Circuit: Disconnect the mirror switch and then disconnect the wiring harness at the mirror motor. Use your multimeter to check the "R" input wire for a short to ground at each point. This will help you isolate whether the short is in the switch, the wiring between the switch and the mirror, or potentially further upstream in the BCM.

Frequently Asked Questions:

• What does the B1712 code mean? The B1712 code means that the right mirror switch input signal wire is shorted to ground. This prevents the right mirror from adjusting properly.

• Can I fix the B1712 code myself? Depending on your mechanical and electrical skills, you might be able to fix it. However, a professional technician has the tools and expertise to diagnose and repair the problem accurately.

• How much does it cost to fix the B1712 code? The cost to fix the B1712 code can vary depending on the cause and the labor rates in your area. It could range from $100 for a simple wiring repair to several hundred dollars if the BCM needs to be replaced.

• What are the symptoms of a faulty mirror switch? The most common symptoms are the inability to adjust the mirror, erratic mirror movement, or the mirror being stuck in one position. The entire switch might also be inoperative.

• Is it safe to drive with the B1712 code present? While it's generally safe to drive, the inability to adjust your mirrors can reduce visibility and increase the risk of an accident. It's best to get the problem fixed as soon as possible.

• Can a bad BCM cause the B1712 code? Yes, although it's less common, a faulty BCM can cause the B1712 code. The BCM controls various electrical functions, including the mirror adjustment.

Conclusion:

The B1712 code indicates a short to ground in the right-side mirror switch circuit. Thoroughly inspect the wiring, switch, and connectors, and consult a wiring diagram to diagnose and repair the issue effectively. Prioritize addressing this issue to ensure safe driving conditions.