B1737 — Mirror Driver Horizontal Switch Circuit Failure #

Note: The description for DTC B1737 may vary between vehicle manufacturers. Always refer to OEM documentation for model-specific information.

• Mirror Driver Horizontal Switch Circuit Malfunction (Ford, Mazda)
• Mirror Adjustment Switch Horizontal Circuit Fault (GM/Chevrolet)
• Power Mirror Switch Horizontal Circuit Error (Chrysler/Dodge/Jeep)

Summary of B1737 — Mirror Driver Horizontal Switch Circuit Failure #

The B1737 diagnostic trouble code (DTC) indicates a problem within the driver-side mirror horizontal adjustment switch circuit. This circuit connects the physical switch, usually located on the driver’s door panel, to the module or motor that moves the mirror left or right. When the vehicle’s body control module (BCM) or mirror control module detects a voltage or continuity issue in this circuit, it records B1737. The issue could stem from faulty wiring, a defective switch, or a failed mirror motor. Although this code does not impact critical driving functions, it can reduce mirror adjustability and driver comfort.

Common Symptoms for B1737 #

A vehicle registering code B1737 will typically show clear signs of mirror adjustment malfunction. While the car remains drivable, the inability to adjust the side view mirror horizontally can be inconvenient and potentially hazardous if not corrected.

• Driver’s side mirror does not move left or right when the switch is pressed
• Mirror adjustment switch feels loose or unresponsive
• Mirror may only move vertically (up/down) but not horizontally (left/right)
• Intermittent operation of the horizontal mirror adjustment
• Check engine light or body control warning may be illuminated (in some models)

Probable Causes for B1737 #

Several factors can trigger the B1737 code, most commonly related to electrical faults or component wear. OEM wiring, especially in door assemblies, is subject to repetitive motion and potential damage. Here are the most frequent root causes, ranked by likelihood:

1. Faulty mirror adjustment switch (internal contact wear or failure)
2. Damaged or pinched wiring harness between the door and body
3. Corroded or loose electrical connectors at the switch or mirror motor
4. Defective driver-side mirror horizontal motor
5. Blown fuse associated with the power mirror circuit
6. Water intrusion or contamination in the switch or connectors
7. Body control module (BCM) internal fault (rare)

Step-by-Step Diagnostic Process for B1737 #

Accurate diagnosis of B1737 requires a systematic approach to rule out common causes and pinpoint the source. Always consult your OEM repair manual for wiring diagrams and connector locations. Here’s a practical, step-by-step guide:

1. Verify the code using a professional scan tool and note any additional related DTCs (such as B1736, B1738).
2. Test mirror switch operation: Try moving the mirror horizontally and vertically. Note any unresponsive directions.
3. Inspect the driver’s mirror switch and connectors for signs of corrosion, water damage, or physical breakage.
4. Check the wiring harness between the door and body—especially where it flexes when opening/closing the door. Look for pinching, fraying, or broken wires.
5. Backprobe the switch output with a multimeter while pressing the horizontal adjustment. Verify voltage or continuity as specified in the OEM diagram.
6. Test the mirror horizontal motor by applying 12V directly to the mirror motor’s horizontal terminals (if accessible) to confirm operation.
7. Check associated fuses and replace any that are blown.
8. If all else checks out, inspect the body control module (BCM) for possible faults, though this is rare.

Possible Repairs for B1737 #

The appropriate repair depends on the root cause identified during diagnosis. Always use OEM parts or approved equivalents to ensure long-term reliability.

• Replace the mirror adjustment switch if internal failure is confirmed
• Repair or replace damaged wiring in the door harness, especially if conductors are broken or shorted
• Clean and secure any corroded or loose connectors
• Replace the mirror horizontal motor if it fails a direct voltage test
• Clear any water intrusion and replace contaminated components as needed
• Replace blown fuses and address the underlying cause of overload
• If required, reprogram or replace the BCM (rare, only after all other causes are ruled out)

Is It Safe to Drive with B1737? #

Yes, you can continue driving with code B1737 present, as this issue does not affect essential vehicle operation, safety systems, or engine performance. However, limited mirror adjustability can reduce your ability to properly set the driver’s side mirror, possibly leading to increased blind spots and decreased safety awareness. For optimal visibility and comfort, it is best to address the issue promptly.

Vehicles Most Commonly Affected by B1737 #

B1737 is a generic body code used by many OEMs, but it is most frequently observed in vehicles with power-adjustable mirrors and advanced body control systems. The following makes and models are commonly reported to trigger this code:

• Ford F-Series, Explorer, Escape
• Mazda 3, 6, CX-5
• Chevrolet Silverado, Malibu, Equinox
• GMC Sierra, Acadia
• Chrysler 200, Town & Country
• Dodge Ram, Charger, Grand Caravan
• Jeep Grand Cherokee, Cherokee

Common Mistakes & Best Practices for B1737 #

When addressing B1737, avoid common missteps that can waste time or money. Following best practices ensures a reliable repair and prevents recurring issues.

• Do not replace the mirror motor or BCM before testing the switch and wiring thoroughly
• Always check for water intrusion and clean/dry connectors before replacing components
• Use OEM wiring diagrams to avoid misdiagnosis
• Inspect door harness flex points, as wires here are prone to fatigue
• After repairs, always clear the code and retest mirror operation

Express FAQ — B1737 #

Still have questions about B1737? Here are quick answers to common concerns:

Q: Will B1737 cause my mirrors to stop working entirely?
A: Usually, only the horizontal (left/right) adjustment is affected. Other mirror functions (vertical, heating, folding) typically remain operational unless there are additional codes or faults.

Q: Can I fix B1737 myself, or do I need a professional?
A: If you have basic automotive electrical skills and access to a multimeter, you can check the switch and wiring yourself. However, diagnosing BCM issues or rewiring door harnesses is often best left to a qualified technician.

For accurate repairs, always consult your vehicle’s OEM repair manual and wiring diagrams. A methodical approach will restore proper mirror function and keep your driving experience safe and comfortable.