B1839 — Wiper Rear Motor Circuit Failure #

Note: The code description may vary depending on the vehicle manufacturer. Always refer to your OEM (Original Equipment Manufacturer) documentation for precise wording.

• B1839 – Rear Wiper Motor Circuit Malfunction (Ford)
• B1839 – Rear Wiper Drive Circuit Failure (Chrysler/Jeep)
• B1839 – Rear Window Wiper Motor Circuit Error (Toyota)
• B1839 – Rear Wiper Motor Electrical Fault (Hyundai/Kia)

Summary of Code B1839 #

B1839 is a diagnostic trouble code (DTC) that indicates the vehicle’s onboard computer has detected an electrical issue in the rear wiper motor circuit. This means that either the signal to or from the motor is out of the expected range, the circuit is open, or there’s a short present. The rear wiper motor is responsible for moving the rear windshield wiper blade, aiding in visibility during rain or snow. When this code appears, it usually means the rear wiper may not work as intended or at all. Addressing this code promptly is important for both safety and comfort, especially in adverse weather.

Common Symptoms for Code B1839 #

Drivers may notice several warning signs when B1839 is present. These symptoms can range from minor inconveniences to complete system failure, depending on the underlying cause. Be attentive to changes in rear wiper behavior, as even intermittent faults can escalate over time.

• Rear wiper does not operate at all
• Rear wiper operates intermittently or erratically
• Rear wiper stops mid-sweep
• Unusual noises from the rear wiper area (grinding, clicking)
• Rear wiper warning light illuminated (if equipped)
• Possible blown fuse for the rear wiper circuit

Most Likely Causes for Code B1839 #

The most common reasons for B1839 typically involve electrical disruptions or component failures within the rear wiper system. Some causes are more frequent than others, so addressing them in order of likelihood can save time and effort.

1. Faulty rear wiper motor (internal open circuit or short)
2. Damaged or corroded wiring/connectors at the wiper motor or switch
3. Blown fuse in the rear wiper circuit
4. Defective rear wiper switch (open contacts or poor continuity)
5. Faulty body control module (BCM) or relay (less common)

Step-by-Step Diagnostic for Code B1839 #

Diagnosing B1839 requires a systematic approach, starting with the basics and moving toward more complex components. Here’s a reliable procedure you can follow to pinpoint the underlying issue:

1. Verify the code with an OBD-II/EOBD scanner and clear any stored codes. Attempt to operate the rear wiper and see if the code returns.
2. Inspect the rear wiper fuse in the vehicle’s fuse box. Replace if blown, but investigate why it failed.
3. Examine the wiring harness and connectors leading to the rear wiper motor for signs of corrosion, damage, or loose connections.
4. Test for power and ground at the rear wiper motor using a multimeter with the switch activated. Confirm both are present.
5. Check the rear wiper motor operation by applying direct battery voltage to see if it runs.
6. Inspect the rear wiper switch for proper function and continuity.
7. Test the body control module (BCM) or relay if all previous steps check out, as a last resort.

Possible Repairs for Code B1839 #

Once the root cause is identified, addressing B1839 is usually straightforward. Choosing the correct repair depends on the diagnostic findings, so always match the solution to the verified fault.

• Replace the rear wiper motor if it fails bench testing
• Repair or replace damaged wiring/connectors as needed
• Replace blown fuse and address any source of electrical overload
• Replace the rear wiper switch if continuity is lost
• Replace the BCM or wiper relay if found faulty after all other components test good

Is It Safe to Drive with Code B1839? #

Yes, but with limitations. Code B1839 does not affect the core drivability of your vehicle. However, if you rely on your rear wiper for visibility—such as during rain, snow, or dusty conditions—driving without a functioning rear wiper can become hazardous. Always use caution and avoid driving in situations where rear visibility is critical until the issue is resolved.

Vehicles Most Commonly Affected by Code B1839 #

While B1839 can appear on a wide range of vehicles, it is most frequently reported on certain makes and models—especially those with rear wiper systems prone to connector or motor issues.

• Ford Escape, Explorer, and Edge
• Kia Sportage and Sorento
• Hyundai Santa Fe and Tucson
• Chrysler Town & Country
• Toyota RAV4 and Highlander
• Jeep Grand Cherokee and Compass

Frequent Mistakes & Best Practices for Code B1839 #

When troubleshooting B1839, some common mistakes can lead to wasted time or unnecessary part replacement. Following best practices improves both efficiency and repair quality.

• Replacing the wiper motor without checking the fuse or wiring first. Always verify the basics before assuming motor failure.
• Ignoring signs of water intrusion or corrosion at connectors. Moisture is a frequent culprit, especially in hatchbacks and SUVs.
• Not testing for power and ground at the motor. A motor can’t run without both; missing either points to an upstream issue.
• Overlooking BCM or relay faults. Rare, but possible if all else checks out.
• Not clearing the code after repairs. Always clear DTCs and confirm fix with a short road test.

Express FAQ for Code B1839 #

Here are concise answers to the most common questions regarding B1839:

• Q: Can B1839 cause other electrical issues?
  A: Typically, no. This code is isolated to the rear wiper circuit. However, if a shared fuse or ground is compromised, other systems may be affected.
• Q: What if the rear wiper works but the code is still present?
  A: Intermittent wiring faults or poor connections can sometimes cause sporadic codes. Carefully inspect wiring and connectors even if symptoms are not constant.