B1747 — Mirror Passenger Horizontal Switch Circuit Short To Battery #

The wording of this diagnostic code may vary by vehicle manufacturer or Original Equipment Manufacturer (OEM).

• B1747 – Right Mirror Horizontal Switch Circuit Short to Battery (Ford, Lincoln, Mercury)
• B1747 – Passenger Side Mirror Horizontal Movement Switch Circuit Shorted (Chrysler, Dodge, Jeep)
• B1747 – Mirror Adjustment Switch Circuit Short to Power (General Motors, some Asian OEMs)

Overview of Code B1747 #

The B1747 diagnostic trouble code (DTC) indicates that the vehicle’s onboard diagnostics (OBD-II/EOBD) system has detected an electrical issue in the passenger side mirror horizontal switch circuit. Specifically, the system has identified a short to battery, meaning a circuit wire or component is unintentionally connected to battery voltage. This signal is crucial for adjusting the mirror horizontally using the interior switch. If you notice your passenger mirror moving on its own, not responding, or behaving erratically, this code is likely behind it. While this is not a safety-critical code, it can be frustrating and should be addressed for comfort and convenience.

Common Symptoms for Code B1747 #

When code B1747 is set, drivers may observe signs that are easy to overlook, but can make daily driving less convenient. The most frequent symptoms include:

• Inability to adjust the passenger side mirror horizontally
• Mirror moves on its own without input
• Mirror adjustment switch feels unresponsive or erratic
• Intermittent operation of the passenger mirror
• Illumination of the check engine light or a dedicated mirror warning on the dashboard (depending on vehicle)

Likely Causes for Code B1747 #

The B1747 code typically stems from a handful of electrical issues. Understanding the root cause can save time and prevent unnecessary parts replacement. The most common causes, listed in order of frequency, are:

1. Damaged or pinched wiring between the mirror switch and the vehicle’s wiring harness
2. Faulty mirror adjustment switch (internal short to battery voltage)
3. Corrosion or water intrusion at electrical connectors
4. Short circuit inside the passenger side mirror motor assembly
5. Incorrect or faulty installation of aftermarket or replacement mirrors/switches
6. Defective control module (rare, but possible if all other causes are ruled out)

Step-by-Step Diagnosis for Code B1747 #

A systematic approach is the best way to pinpoint the source of a B1747 code. Follow these steps to track down the culprit and avoid chasing electrical ghosts:

• Verify the code using a scan tool and confirm that B1747 is present.
• Inspect fuse(s) related to the mirror circuit for signs of blowing or overcurrent.
• Perform a visual inspection of the mirror switch, wiring, and connectors for damage, pinching, or corrosion.
• Unplug the mirror switch and check for battery voltage at the switch harness using a multimeter.
• Test the switch itself for internal shorts between terminals with the switch removed from the circuit.
• Check the mirror motor assembly by disconnecting it and seeing if the code clears or if the wiring shows continuity to battery voltage where it shouldn’t.
• Scan for additional codes that might indicate broader wiring or module issues.
• Consult OEM wiring diagrams if necessary to confirm correct pinouts and circuit design.

Possible Repairs for Code B1747 #

Repairs for B1747 are typically straightforward once the cause is isolated. Always ensure the root issue is addressed before replacing parts. Common fixes include:

• Repairing or replacing damaged or shorted wiring in the mirror circuit
• Replacing the passenger mirror adjustment switch
• Cleaning or replacing corroded connectors at the door or mirror assembly
• Replacing the passenger side mirror motor assembly if internally shorted
• Correcting any improper aftermarket wiring or installations
• Replacing the control module (rare; only if all other issues are ruled out and module failure is confirmed)

Is it Safe to Drive with Code B1747? #

Yes, you can continue driving with code B1747 present, but with limitations. This code does not affect the vehicle’s safety systems or drivability. However, you may lose the ability to adjust the passenger side mirror horizontally, which can impact visibility and convenience. If the mirror moves on its own, it could become a distraction. It’s wise to repair the issue soon, especially if you frequently need to adjust your mirrors for safe lane changes.

Vehicles Most Commonly Affected by Code B1747 #

While B1747 can be found in a wide range of vehicles, it is most frequently reported in:

• Ford, Lincoln, and Mercury cars and trucks (especially late 1990s–2010s)
• Chrysler, Dodge, and Jeep vehicles with power mirrors
• Certain General Motors models with power folding or memory mirrors
• Some Asian and European models with advanced mirror features

Common Mistakes & Best Practices for Code B1747 #

Misdiagnosis can lead to wasted time and money. Avoid these pitfalls and follow best practices for a smoother repair experience:

• Replacing the mirror switch or entire mirror assembly without first checking for wiring damage
• Ignoring signs of water intrusion or corrosion in door harness connectors
• Overlooking aftermarket or recent repair work that may have altered factory wiring
• Not clearing the code after repairs to confirm the fix
• Neglecting to use OEM wiring diagrams when tracing the circuit

Quick FAQ for Code B1747 #

Here are answers to some of the most common questions about B1747:

• Q: Will B1747 cause my check engine light?
  A: Not in most vehicles; it may trigger a specific warning or store the code without a warning light.
• Q: Can I fix B1747 myself?
  A: If you’re comfortable with basic electrical diagnostics (multimeter, visual inspection), you may be able to locate and repair simple wiring issues or replace the switch. For complex wiring or module faults, professional help is recommended.