Engine-Codes - Lincoln - B12AE LINCOLN

B12AE LINCOLN - Passenger Heated Seat Relay Drive Circuit Open Or Shorted to Ground

Repair Importance Level: 3/3
Repair Difficulty Level: 3/3  What is this?
Table of contents

B12AE LINCOLN Possible Causes

  • 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 is the B12AE LINCOLN code repair?

Start by checking the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector's pins.

What is the cost to diagnose the B12AE LINCOLN code

Labor: 1.0

The cost to diagnose the B12AE LINCOLN code is 1.0 hour of labor. The auto repair labor rates vary widely across the country, and even within the same city. Most auto repairs shops charge between $75 and $150 per hour.
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Possible Symptoms

  • Engine Light ON (or Service Engine Soon Warning Light)


The Heating, Ventilation, and Air-Conditioning (HVAC) Module contains the passenger 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 passenger 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 passenger heated seat relay coil when the engine is running. The ground is supplied to the opposite side of the passenger relay coil by the HVAC module from the passenger heated seat relay drive circuit when the passenger 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 passenger heater mat circuit. The passenger heater mats are directly connected to ground circuit completing the electrical circuit to heat the seat.

More Information

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