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Engine-Codes – Mercury – B1694 Mercury

B1694 Mercury Code - Autolamp On Circuit Open

Quick Answer

The B1694 diagnostic trouble code (DTC) is specific to Mercury vehicles and indicates an issue with the autolamp on circuit being open. Common causes include Faulty Light Sensor: The ambient light sensor may be malfunctioning, failing to send the correct signals to the BCM, Damaged Wiring: Physical damage to the wiring harness associated with the autolamp circuit can cause an open circuit, Defective Body Control Module (BCM): A failure within the BCM itself can prevent it from processing the signals necessary for the autolamp function. 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
B1694 Mercury indicates Autolamp On Circuit Open.
Common causes
Common causes include Faulty Light Sensor: The ambient light sensor may be malfunctioning, failing to send the correct signals to the BCM, Damaged Wiring: Physical damage to the wiring harness associated with the autolamp circuit can cause an open circuit, Defective Body Control Module (BCM): A failure within the BCM itself can prevent it from processing the signals necessary for the autolamp function.
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.
What is this?
Table of contents Created and updated by William Orellana on Oct 03, 2024
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Code B1694 Mercury Description

The B1694 diagnostic trouble code (DTC) is specific to Mercury vehicles and indicates an issue with the autolamp on circuit being open. This code typically arises when the vehicle's body control module (BCM) detects that the circuit responsible for controlling the automatic headlamp function is not completing as expected. The autolamp system is designed to automatically turn on the headlights when ambient light conditions dictate, such as during dusk or in tunnels.

OBDII Code B1694 Mercury - Autolamp On Circuit Open
B1694 Mercury Code - Autolamp On Circuit Open

Common Causes of B1694 Mercury

  1. Faulty Light Sensor: The ambient light sensor may be malfunctioning, failing to send the correct signals to the BCM.
  2. Damaged Wiring: Physical damage to the wiring harness associated with the autolamp circuit can cause an open circuit.
  3. Defective Body Control Module (BCM): A failure within the BCM itself can prevent it from processing the signals necessary for the autolamp function.
  4. Corroded Connectors: Corrosion at the connectors can lead to poor electrical connections, resulting in an open circuit.
  5. Blown Fuse: A blown fuse in the lighting circuit can interrupt the flow of electricity, triggering the B1694 code.

Symptoms of B1694 Mercury

  1. Headlights Not Activating Automatically: The most direct symptom is the failure of the headlights to turn on automatically in low-light conditions.
  2. Dashboard Warning Lights: The vehicle may display warning lights on the dashboard, indicating a problem with the lighting system.
  3. Manual Headlight Operation Required: Drivers may find themselves needing to manually turn on the headlights, which can be inconvenient and lead to safety issues.
  4. Inconsistent Headlight Functionality: The headlights may flicker or operate inconsistently, indicating an underlying electrical issue.
  5. Increased Battery Drain: If the headlights are left on manually, it could lead to battery drain, especially if the driver forgets to turn them off.

How to Fix B1694 Mercury

  1. Diagnostic Scan: Begin with a diagnostic scan to confirm the B1694 code and check for any additional codes that may provide insight into the issue.
  2. Visual Inspection: Conduct a thorough visual inspection of the wiring harness, connectors, and the light sensor for any signs of damage or corrosion.
  3. Test the Light Sensor: Use a multimeter to test the ambient light sensor's functionality and ensure it is sending the correct signals to the BCM.
  4. Check the BCM: If the sensor is functioning correctly, test the BCM for faults. If necessary, reprogram or replace the BCM.
  5. Repair or Replace Wiring: If damaged wiring or connectors are found, repair or replace them as needed to restore the integrity of the circuit.

Cost to Fix B1694 Mercury

** Repair costs for addressing the B1694 code can vary widely based on the specific issue identified during diagnosis. On average, the total cost may range from $100 to $600. This estimate includes parts and labor, with labor rates typically falling between $80 and $150 per hour. Factors such as location, vehicle make and model, and engine type can influence these rates. For instance, metropolitan areas or dealerships may charge higher rates, while independent shops may offer more competitive pricing. It is advisable to consult local repair shops for a more precise estimate tailored to the specific vehicle and issue at hand.

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about B1694 Mercury Code

1. What does the OBDII code B1694 mean for a Mercury vehicle?

The code B1694 indicates that the Autolamp On Circuit is open, meaning there’s an issue in the wiring or components responsible for the automatic headlamp system.

2. What are the symptoms of a B1694 code in a Mercury?

Common symptoms include the automatic headlamps not turning on or off as expected, the headlamps staying on continuously, or a warning light on the dashboard.

3. What causes the B1694 code to appear?

The most common causes include a faulty Autolamp control module, damaged or corroded wiring, a defective light sensor, or a blown fuse in the Autolamp circuit.

4. Can a bad light sensor trigger the B1694 code?

Yes, a malfunctioning ambient light sensor can cause the Autolamp On Circuit to fail, leading to the B1694 code.

5. How can I diagnose the B1694 code on a Mercury?

Start by checking the wiring and connectors for damage or corrosion. Test the Autolamp control module and light sensor for proper operation. Use a scan tool to confirm the code and pinpoint the fault.

6. Is it safe to drive with the B1694 code on a Mercury?

While it may be safe to drive, the automatic headlamp system may not function correctly, reducing visibility or compliance with lighting regulations in certain conditions.

7. How do you fix the B1694 code on a Mercury?

Repairs may include replacing a damaged light sensor, fixing or replacing faulty wiring, repairing the Autolamp control module, or replacing a blown fuse.

8. Can I reset the B1694 code without making repairs?

Clearing the code with a scan tool might turn off the warning temporarily, but the code will likely return until the underlying issue is resolved.

9. What tools are needed to troubleshoot the B1694 code?

You'll need a scan tool, multimeter, and possibly wiring diagrams for your Mercury model to diagnose and fix the issue.

10. How much does it cost to repair a B1694 code on a Mercury?

Repair costs can vary depending on the issue, ranging from $50 for a fuse replacement to several hundred dollars for a new Autolamp control module or professional diagnostics.

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