B1477 — Wiper Hi/Low Circuit Motor Short To Ground #

Note: The wording of this Diagnostic Trouble Code (DTC) may vary depending on the vehicle manufacturer. Always consult your OEM (Original Equipment Manufacturer) service manual for precise terminology and circuit diagrams.

• Wiper Hi/Low Circuit Short to Ground (Chrysler, Ford, GM)
• Front Wiper Motor High/Low Circuit Shorted to Ground (Nissan, Toyota)
• Wiper Motor Speed Control Circuit Short GND (Volkswagen, Hyundai)

Summary of code B1477 #

The B1477 code signals that the vehicle’s Body Control Module (BCM) or a related controller has detected a short-to-ground condition in the wiper motor high/low speed circuit. In simpler terms, this means that the wiring or component responsible for switching between high and low wiper speeds is unintentionally connected to ground, disrupting normal operation. This code is most often seen in vehicles with electronically controlled wiper systems, where the BCM closely monitors the electrical integrity of all wiper circuits. The issue can result from wiring damage, connector problems, or internal faults within the wiper motor assembly itself. While this code does not indicate a direct safety threat in most cases, it can cause unpredictable wiper behavior or total loss of wiper function, which can be hazardous in poor weather conditions.

Common symptoms for code B1477 #

A vehicle with a B1477 code typically presents one or more of the following symptoms. These issues may be intermittent or continuous, depending on the nature of the short:

• Windshield wipers fail to operate at one or more speed settings (usually high or low).
• Wipers may only work on one speed (often defaulting to “low”).
• Wipers stop working entirely or operate erratically.
• Blown wiper fuse, which disables all wiper operation.
• Warning light or message on the dashboard related to wipers or electrical faults.

Probable causes for code B1477 (by frequency) #

The B1477 code is most commonly triggered by electrical faults. The following list orders likely causes from most to least frequent:

1. Damaged wiring harness – Chafed, pinched, or corroded wires in the wiper motor circuit contacting metal and grounding out.
2. Faulty wiper motor – Internal short to ground within the wiper motor assembly, especially in older or high-mileage vehicles.
3. Corroded or loose connectors – Moisture intrusion, corrosion, or poor contact at the wiper motor or BCM connectors.
4. Failed wiper relay or control module – Internal relay or solid-state driver shorted to ground.
5. Incorrect or failed replacement parts – Aftermarket or mismatched parts not meeting OEM specifications.

Step-by-step diagnosis for code B1477 #

Diagnosing B1477 involves a systematic approach to isolate the short-to-ground condition. Always begin with a visual inspection and basic electrical safety precautions:

• 1. Retrieve all codes and freeze-frame data using a scan tool. Clear codes and see if B1477 returns immediately.
• 2. Inspect wiper fuse(s) and replace if blown. If the fuse blows again, a direct short is likely.
• 3. Visually inspect the wiring harness from the BCM to the wiper motor for damage, pinched spots, or exposed wires contacting metal.
• 4. Check all connectors at the wiper motor and BCM for corrosion, bent pins, or water intrusion.
• 5. Disconnect the wiper motor and use a multimeter to test for continuity to ground on the high/low speed circuit wires. No continuity should be present with the ignition off.
• 6. Test the wiper motor independently by applying power and ground (per OEM service manual) to verify internal shorts.
• 7. Test the wiper relay or control module for signs of internal failure or shorting.
• 8. Repair any faults found, clear the code, and retest the system.

Possible repairs for code B1477 #

Repairs for B1477 must directly address the root cause of the short-to-ground. The following actions correspond to the most likely sources:

• Repair or replace damaged wiring harness sections and ensure proper routing away from moving parts and sharp edges.
• Replace the wiper motor if internal shorting is confirmed.
• Clean, repair, or replace corroded or damaged connectors at both the wiper motor and BCM.
• Replace the wiper relay or control module if diagnosed as faulty (follow OEM procedures).
• Install only OEM-approved replacement parts to ensure correct electrical compatibility.

Is it safe to drive with code B1477? #

Driving with code B1477 is limited and potentially unsafe in inclement weather. If the wipers are inoperative or cannot switch speeds, visibility in rain or snow may be impaired, posing a safety risk. If the weather is dry and clear, you may drive a short distance to a repair facility, but do not attempt to drive in wet or unpredictable conditions until the issue is resolved. Always prioritize a properly functioning wiper system for safe driving.

Vehicles most commonly affected by code B1477 #

While B1477 can be found across many brands, it’s most commonly reported on models with electronically controlled wiper circuits, especially from the following manufacturers:

• Ford (Escape, F-150, Explorer)
• Chrysler/Dodge/Jeep (Grand Cherokee, Ram, Pacifica)
• General Motors (Chevrolet Silverado, Malibu, Equinox, GMC Sierra)
• Nissan (Altima, Rogue, Pathfinder)
• Toyota (Camry, Corolla, Tacoma)
• Volkswagen (Jetta, Passat, Tiguan)

Common mistakes & best practices when dealing with B1477 #

Misdiagnosis or incomplete repairs can lead to recurring issues with B1477. Avoid these pitfalls by following best diagnostic practices:

• Replacing the wiper motor without inspecting wiring or connectors, leading to repeat failures.
• Ignoring signs of water intrusion or corrosion at connectors, which can cause intermittent shorts.
• Using non-OEM parts that do not match circuit specifications, resulting in compatibility issues.
• Skipping continuity tests on the affected circuit before and after repairs.

Quick FAQ for code B1477 #

Q: Can a blown fuse alone cause B1477?
A: A blown fuse is often a symptom, not the root cause. The fuse protects the circuit and usually blows because of a short to ground, which B1477 is meant to identify.

Q: Is it expensive to fix B1477?
A: Repair costs vary. Simple wiring repairs may be affordable, while wiper motor or module replacements can be more expensive. Early diagnosis usually prevents more costly damage.