B12A4 - Mode Door Actuator Drive Circuit Shorted To Battery Voltage
B12A4 Possible Causes
- Stuck or damaged linkage or door
- Faulty Mode Door Actuator
- Mode Door Actuator harness is open or shorted
- Mode Door Actuator circuit poor electrical connection
- Electronic Manual Temperature Control (EMTC) Module
- Electronic Automatic Temperature Control (EATC) Module
How do I fix code B12A4
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 B12A4 code
Labor: 1.0The cost of diagnosing the B12A4 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.
B12A4 Possible Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
B12A4 MeaningUnder normal operation, to rotate the mode door actuator clockwise, the Electronic Manual Temperature Control (EMTC) or Electronic Automatic Temperature Control (EATC) module supplies voltage and ground to the floor/defrost/panel mode door actuator motor through the circuit. To rotate the mode door actuator counterclockwise, the EMTC module or EATC module reverses the voltage and ground circuits.
The mode door actuator feedback resistor is supplied a ground from the EMTC module or EATC module and a 5-volt reference voltage. The EMTC module or EATC module reads the voltage on the mode door actuator feedback circuit to determine the mode door actuator position by the position of the actuator feedback resistor wiper arm.
B12A4 More InformationNeed more information on how to fix the B12A4 code?
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