AutoCodes – Mercury – B12AB Mercury

B12AB Mercury Code - Drivers Heated Seat Relay Drive Circuit Shorted To Battery Voltage

Quick Answer

The Heating, Ventilation, and Air-Conditioning (HVAC) Module contains the driver heated seat control button and indicator. Common causes include Faulty Heater Seat Relay, Faulty Heater Mat, Heater Mat harness is open or shorted. Severity is Low - monitor the vehicle and repair when practical. The vehicle can usually be driven if no severe symptoms are present, but symptoms should be checked before extended driving.

What it means: B12AB Mercury indicates Drivers Heated Seat Relay Drive Circuit Shorted To Battery Voltage.
Common causes: Common causes include Faulty Heater Seat Relay, Faulty Heater Mat, Heater Mat harness is open or shorted.
Severity: Low - monitor the vehicle and repair when practical.
Can I drive?: The vehicle can usually be driven if no severe symptoms are present, but symptoms should be checked before extended driving.

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Code Popularity 623

How popular is this code, among other codes? Low

Repair Importance Level

Low (Monitor) (1 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Nov 29, 2024

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B12AB Mercury Description

The Heating, Ventilation, and Air-Conditioning (HVAC) Module contains the driver heated seat control button and indicator. The heated seat system functions independently from the climate control system. A heated seat relay is located underneath the driver seat cushion frame. There are 2 voltage supplies to the heated seat relay. Voltage is supplied from the Smart Junction Box (SJB) heated seat relay enable circuit to the driver heated seat relay coil when the engine is running. Ground is supplied to the opposite side of the driver relay coil by the HVAC module driver heated seat relay drive circuit when the driver heated seat switch button is pressed to energize the relay. This closes the relay contacts to supply battery voltage from the SJB circuit to the driver heater mat circuit. The driver heater mats are directly connected to ground circuit completing the electrical circuit to heat the seat.

OBDII Code B12AB Mercury - Drivers Heated Seat Relay Drive Circuit Shorted To Battery Voltage - AutoCodes.com — B12AB Mercury Code - Drivers Heated Seat Relay Drive Circuit Shorted To Battery Voltage

What does this mean?

What are the Possible Causes of the DTC B12AB Mercury?

Faulty Heater Seat Relay
Faulty Heater Mat
Heater Mat harness is open or shorted
Heater Mat circuit poor electrical connection
Faulty Heating, Ventilation, and Air-Conditioning (HVAC) Module

How to Fix the DTC B12AB 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 B12AB 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.

Need more information about the B12AB Mercury code?

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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 B12AB Mercury Code

1. What are the common symptoms of OBDII code B12AB in a Mercury related to the driver's heated seat relay drive circuit being shorted to battery voltage?

- The common symptoms include the driver's heated seat not functioning properly or not turning off, along with a possible burning smell or seat overheating.

2. What are the possible causes of the driver's heated seat relay drive circuit being shorted to battery voltage in a Mercury?

- The main causes can be a damaged relay, a short circuit in the wiring, or a malfunctioning seat heating element.

3. How can I diagnose the issue with OBDII code B12AB in a Mercury related to the driver's heated seat relay drive circuit shorted to battery voltage?

- Use a multimeter to test the continuity of the wiring, check the condition of the relay, and inspect the seat heating element for any visible damage.

4. Can I continue driving my Mercury with OBDII code B12AB indicating a shorted driver's heated seat relay drive circuit?

- It is not recommended to continue driving the vehicle with this issue as it can pose a safety risk due to potential overheating of the seat.

5. How can the driver's heated seat relay drive circuit shorted to battery voltage in a Mercury be repaired?

- The repair typically involves replacing the faulty relay, repairing any damaged wiring, and potentially replacing the seat heating element if necessary.

6. Are there any safety precautions to take when working on the driver's heated seat relay drive circuit in a Mercury?

- Ensure the vehicle is turned off, disconnect the battery, and allow the seat to cool down before attempting any repairs to avoid burns or electrical shock.

7. Can a DIY enthusiast fix the issue with OBDII code B12AB related to the driver's heated seat relay drive circuit in a Mercury?

- Depending on their skill level and experience with automotive electrical systems, a DIY enthusiast may be able to diagnose and repair the issue with proper guidance and tools.

8. Is it common for the driver's heated seat relay drive circuit to short to battery voltage in a Mercury?

- While it is not extremely common, issues with the driver's heated seat relay drive circuit can occur due to wear and tear or electrical faults over time.

9. Will resetting the OBDII code B12AB clear the issue with the driver's heated seat relay drive circuit in a Mercury?

- Resetting the code may temporarily clear the warning light, but it will not fix the underlying problem causing the circuit to short to battery voltage.

10. How long does it typically take to repair the driver's heated seat relay drive circuit issue indicated by OBDII code B12AB in a Mercury?

- The repair duration can vary depending on the extent of the damage and the availability of replacement parts, but it may take a few hours to a day to complete the repair.