B1789 Code - Mirror Passenger Down Circuit Short To Ground
Quick Answer
The B1789 diagnostic trouble code (DTC) indicates that there is a short to ground in the mirror passenger down circuit of the vehicle. Common causes include Short circuit in the mirror wiring harness, Faulty mirror control switch, Water ingress causing corrosion in the mirror circuit. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- B1789 indicates Mirror Passenger Down Circuit Short To Ground.
- Common causes
- Common causes include Short circuit in the mirror wiring harness, Faulty mirror control switch, Water ingress causing corrosion in the mirror circuit.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
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Code B1789 Description
The B1789 diagnostic trouble code (DTC) indicates that there is a short to ground in the mirror passenger down circuit of the vehicle. This means that there is an abnormal connection between the power supply and the ground in the circuit that controls the passenger side mirror's downward movement. This issue can affect the functionality of the mirror, preventing it from moving as intended. It may also cause electrical malfunctions in the vehicle's mirror control system.
Common Causes of B1789
- Short circuit in the mirror wiring harness.
- Faulty mirror control switch.
- Water ingress causing corrosion in the mirror circuit.
- Damaged mirror motor.
- Electrical issues in the vehicle's body control module.
Symptoms of B1789
- Passenger side mirror not moving up or down as commanded.
- Mirror control buttons not responding.
- Erratic movement of the passenger side mirror.
- Warning light on the dashboard related to mirror control system.
- Electrical burning smell coming from the mirror area.
How to Fix B1789
- Begin by diagnosing the specific location of the short circuit using a multimeter to test the continuity of the mirror down circuit.
- Inspect the mirror wiring harness for any visible damage or signs of wear. Repair or replace any damaged wiring as necessary.
- Check the mirror control switch for proper functionality. Replace the switch if it is found to be faulty.
- Test the mirror motor for proper operation. If the motor is malfunctioning, replace it with a new one.
- Clear the DTCs from the vehicle's system using an OBD-II scanner after completing the repair to ensure the issue is resolved.
Cost to Fix B1789
The cost of repairing a B1789 code can vary depending on the specific cause of the issue and the labor rates in your area. On average, the repair cost for this type of issue can range from $100 to $300, including parts and labor. However, it is important to note that prices can fluctuate based on the severity of the problem and the type of vehicle being serviced. It's recommended to consult with a professional mechanic to get an accurate estimate for your specific situation.
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Frequently Asked Questions about B1789 Code
1. What does the OBDII code B1789 mean?
B1789 indicates a short to ground in the passenger mirror down circuit, which affects the functionality of the mirror's vertical adjustment.
2. What are the common symptoms of the B1789 code?
Symptoms include the passenger-side mirror not moving downward, limited adjustability, or no response when using the mirror control switch.
3. What causes the B1789 code to appear?
The code is typically caused by damaged wiring, a short to ground in the mirror circuit, a faulty mirror motor, or a malfunctioning mirror control switch.
4. How can I diagnose the B1789 code?
Start by inspecting the passenger mirror wiring for damage or exposed wires, test the mirror motor for proper operation, and check the mirror control switch for continuity.
5. Can a faulty mirror motor trigger the B1789 code?
Yes, a defective passenger-side mirror motor can create a short to ground, leading to this code.
6. Is the B1789 code critical to address immediately?
While it won’t affect vehicle safety or drivability, it’s best to repair it promptly to restore full functionality to the passenger-side mirror.
7. How do I fix the B1789 code?
Repairs may include replacing damaged wiring, repairing the ground connection, replacing the mirror motor, or replacing the mirror control switch.
8. Can clearing the B1789 code fix the issue?
Clearing the code without addressing the root cause will likely result in the code returning, as the underlying problem still exists.
9. What tools are needed to repair the B1789 code?
You’ll typically need a multimeter for electrical testing, wiring repair tools, and potentially a replacement mirror motor or control switch.
10. Can the B1789 code be caused by a blown fuse?
While uncommon, a blown fuse in the mirror control circuit could contribute to electrical issues, so checking fuses is a good step in the diagnostic process.
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