AutoCodes – Mercury – B1793 Mercury

B1793 Mercury Code - Autolamp Sensor Input Circuit Short To Ground

Quick Answer

The Smart Junction Box (SJB) sends a voltage signal to the headlamp switch and the light sensor. Common causes include Faulty Light Sensor, Light Sensor harness is open or shorted, Light Sensor circuit poor electrical connection. 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: B1793 Mercury indicates Autolamp Sensor Input Circuit Short To Ground.
Common causes: Common causes include Faulty Light Sensor, Light Sensor harness is open or shorted, Light Sensor circuit poor electrical connection.
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 Popularity 460

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Oct 16, 2022

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B1793 Mercury Description

The Smart Junction Box (SJB) sends a voltage signal to the headlamp switch and the light sensor.
When the headlamp switch is placed in the AUTOLAMPS ON position, the voltage signal is routed to ground. When the SJB detects the headlamp switch in the AUTOLAMPS ON position, the SJB monitors the light sensor input. The light sensor determines the amount of light based on the input received from the ambient lighting conditions. When the ambient level has reached a point (determined by the internal programming of the SJB ), the SJB provides voltage to the headlamps, parking and license plate lamps. The Diagnostic Trouble Code (DTC) sets when the SJB detects a short to ground from the light sensor input circuit.

OBDII Code B1793 Mercury - Autolamp Sensor Input Circuit Short To Ground - AutoCodes.com — B1793 Mercury Code - Autolamp Sensor Input Circuit Short To Ground

What does this mean?

What are the Possible Causes of the DTC B1793 Mercury?

Faulty Light Sensor
Light Sensor harness is open or shorted
Light Sensor circuit poor electrical connection
Faulty Headlamp Switch
Faulty Smart Junction Box (SJB)

How to Fix the DTC B1793 Mercury?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the B1793 Mercury code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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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 B1793 Mercury Code

1. What are the common symptoms of OBDII code B1793 - Autolamp Sensor Input Circuit Short To Ground in a Mercury vehicle?

- Common symptoms include malfunctioning autolamp system, automatic headlights not functioning properly, and dashboard warning light illuminated.

2. What could cause the Autolamp Sensor Input Circuit Short To Ground code (B1793) in a Mercury vehicle?

- Possible causes include a damaged autolamp sensor, short circuit in the wiring, faulty control module, or a malfunctioning light sensor.

3. How can I diagnose the Autolamp Sensor Input Circuit Short To Ground issue in my Mercury car?

- To diagnose this issue, you can use an OBDII scanner to retrieve the specific trouble code, visually inspect the autolamp sensor and wiring for any damage, and perform a continuity test on the circuit.

4. Is it safe to continue driving my Mercury with the B1793 OBDII code related to the Autolamp Sensor Input Circuit Short To Ground?

- It is not recommended to drive the vehicle with this code as it may lead to unpredictable behavior of the autolamp system, potentially affecting visibility during low-light conditions.

5. Can I repair the Autolamp Sensor Input Circuit Short To Ground issue in my Mercury at home?

- Depending on your skill level and access to tools, you may be able to repair this issue at home by replacing the damaged sensor or repairing the wiring. However, it is advisable to consult a professional mechanic for accurate diagnosis and repair.

6. How much does it typically cost to fix the Autolamp Sensor Input Circuit Short To Ground problem in a Mercury vehicle?

- The cost of repairing this issue can vary depending on the exact cause of the problem, the labor rates in your area, and the cost of replacement parts. It is recommended to obtain quotes from auto repair shops for an accurate estimate.

7. Will resetting the OBDII code B1793 related to the Autolamp Sensor Input Circuit Short To Ground solve the issue temporarily?

- Resetting the code may temporarily turn off the dashboard warning light, but it will not fix the underlying problem causing the code. It is important to diagnose and repair the issue to prevent further complications.

8. Are there any preventive maintenance tips to avoid encountering the Autolamp Sensor Input Circuit Short To Ground code in a Mercury vehicle?

- To prevent this issue, you can regularly inspect the autolamp system components for any signs of wear or damage, avoid water exposure to sensitive areas, and address any electrical issues promptly.

9. Can extreme weather conditions contribute to triggering the Autolamp Sensor Input Circuit Short To Ground code in a Mercury car?

- Yes, extreme weather conditions such as heavy rain, snow, or extreme heat can potentially damage the autolamp sensor or wiring, leading to a short circuit and triggering the B1793 trouble code.

10. How long does it typically take for a mechanic to diagnose and repair the Autolamp Sensor Input Circuit Short To Ground issue in a Mercury vehicle?

- The diagnosis and repair time can vary depending on the complexity of the issue, the availability of replacement parts, and the workload of the auto repair shop. It is advisable to inquire about the estimated timeframe with your chosen mechanic.