B1612 — Wiper Rear Mode Select Switch Circuit Open #

Note: The description of DTC B1612 may vary between manufacturers.

• B1612: Rear Wiper Mode Switch Open Circuit (Ford, Mazda)
• B1612: Rear Wiper Switch Circuit Malfunction (Toyota, Lexus)
• B1612: Rear Wiper Control Switch Open (Hyundai, Kia)

Summary of DTC B1612 #

The B1612 diagnostic trouble code (DTC) indicates that the vehicle’s onboard diagnostic system has detected an open circuit in the rear wiper mode select switch. This switch allows the driver to control the various operating modes of the rear windshield wiper (such as intermittent, low, or off). When the circuit is “open,” it means that electrical continuity has been lost—typically due to a wiring or switch fault. As a result, rear wiper functionality may be impaired or completely inoperative. While this issue is not usually critical for immediate vehicle safety, it can affect rear visibility, especially in adverse weather. Addressing the root cause promptly is important for both convenience and safety.

Frequent Symptoms for Code B1612 #

Drivers may notice a range of symptoms when B1612 is set. Most commonly, the rear wiper no longer responds to switch inputs, or only works in certain modes. Sometimes, the malfunction indicator light or a specific warning for the rear wiper may illuminate on the dashboard. In some cases, the rear wiper might activate unexpectedly or behave erratically.

• Rear wiper does not operate at all
• Rear wiper only works in one mode (e.g., intermittent only)
• Dashboard warning or malfunction indicator light present
• Inconsistent or erratic rear wiper operation

Probable Causes for Code B1612 #

The root causes for a B1612 code are typically related to electrical faults. The most frequent issues include switch failure, wiring problems, or connector issues. Less commonly, a fault within the Body Control Module (BCM) or a rear wiper motor malfunction can trigger this code.

1. Faulty rear wiper mode select switch
2. Open or damaged wiring between switch and control module
3. Corroded or loose electrical connectors
4. Malfunctioning Body Control Module (BCM)
5. Faulty rear wiper motor (rare)

Step-by-Step Diagnosis for Code B1612 #

Diagnosing B1612 involves systematic checks of the switch, wiring, and related modules. Always begin with a visual inspection and use a multimeter to verify circuit continuity. OEM wiring diagrams and diagnostic procedures should be referenced for precise pin locations and values.

• Verify the code with a diagnostic scan tool and clear any stored codes.
• Visually inspect the rear wiper switch and its wiring harness for damage or corrosion.
• Check for loose, disconnected, or corroded connectors at the rear wiper switch and BCM.
• Use a multimeter to test continuity in the wiring from the switch to the BCM.
• Test the rear wiper mode select switch for proper function (check OEM specs for resistance values).
• If all wiring and the switch test good, consider BCM diagnostics as per the manufacturer’s service manual.
• Test the rear wiper motor if the above steps do not resolve the issue.

Possible Repairs for Code B1612 #

Once the source of the open circuit is identified, the corresponding repair can be performed. Ensure all repairs use quality components and follow OEM procedures to prevent recurrence of the fault.

• Replace the rear wiper mode select switch if it tests faulty.
• Repair or replace any damaged wiring between the switch and the BCM.
• Clean and secure all electrical connectors in the circuit.
• Replace or reprogram the BCM if it is determined to be at fault.
• Replace the rear wiper motor if other components are confirmed operational.

Is It Safe to Drive with Code B1612? #

Limited: In most cases, it is safe to drive with code B1612, but visibility may be compromised if rain or snow accumulates on the rear window. If your driving conditions regularly require clear rear visibility, address this issue as soon as possible. For vehicles operated in fair weather, this code is not an immediate safety risk but should not be ignored.

Vehicles Most Commonly Affected by Code B1612 #

While B1612 can appear in many vehicles equipped with a rear wiper, it is most frequently reported in certain makes and models that use similar rear wiper control architectures. The following vehicles are more likely to experience this code:

• Ford Escape, Focus, Explorer
• Mazda CX-5, Mazda3 Hatchback
• Toyota RAV4, Highlander
• Hyundai Santa Fe, Tucson
• Kia Sorento, Sportage
• Lexus RX series

Common Mistakes & Best Practices for Code B1612 #

When diagnosing and repairing B1612, technicians sometimes overlook the basics—such as connector condition or performing a simple continuity check. Rushed replacements of expensive modules without confirming switch and wiring integrity are another frequent pitfall.

• Not checking for corrosion or looseness in connectors before replacing parts
• Replacing the rear wiper motor or BCM prematurely
• Forgetting to reset and retest the system after repairs
• Neglecting to use OEM wiring diagrams for accurate diagnosis
• Not verifying the issue with a scan tool after repairs are completed

Express FAQ for Code B1612 #

Here are quick answers to frequent questions about this code:

• Q: Can I fix B1612 myself?
  A: If you’re comfortable with basic automotive electrical work, you can check connectors and wiring. For switch or module replacement, professional help is recommended.
• Q: Will disconnecting the battery clear the code?
  A: No, B1612 typically requires a diagnostic scan tool to clear. The fault will also return if the underlying issue is not repaired.
• Q: Does B1612 mean my rear wiper motor is bad?
  A: Not necessarily; the code refers to the switch circuit. The motor is rarely the cause unless all other components check out.