Drivers Heated Seat Relay Drive Circuit Shorted To Battery Voltage
Table of contents
B12AB MERCURY 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 do I fix code B12AB MERCURY?
Check 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.
Cost of diagnosing the B12AB MERCURY code
The cost of diagnosing the B12AB MERCURY code is 1.0 hour of labor. The auto repair labor rates vary by location, your vehicle’s make and model, and even your engine type. Most auto repairs shops charge between $75 and $150 per hour.
Possible Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
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.