Engine-Codes - Generic - B12AF

B12AF - Front Blower Motor Relay Drive Circuit Shorted To Battery Voltage

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

B12AF Possible Causes

  • Faulty Front Blower Motor Fuse
  • Faulty Front Blower Motor Relay
  • Front Blower Motor Relay harness is open or shorted
  • Front Blower Motor Relay circuit poor electrical connection
  • Faulty Front Blower Motor
  • Faulty Electronic Manual Temperature Control (EMTC) Module

How is the B12AF 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 B12AF code

Labor: 1.0

The cost to diagnose the B12AF 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.

Possible Symptoms

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

B12AF Meaning

Under normal operation, the blower motor relay coil receives ignition voltage through the circuit. The coil receives ground from the Electronic Manual Temperature Control (EMTC) Module through the circuit if any function selector position but OFF is selected. Voltage is supplied to the relay switch contact. When the relay coil is energized, the voltage is delivered to the blower motor through the circuit. Ground for the blower motor is provided through the circuit from the blower resistor or the blower switch (HI). The blower resistor and blower switch are grounded through the circuit.

More Information

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Information for specific makes

  • B12AF FORD Front Blower Motor Relay Drive Circuit Shorted To Battery Voltage
  • B12AF LINCOLN Front Blower Motor Relay Drive Circuit Shorted To Battery Voltage
  • B12AF MERCURY Front Blower Motor Relay Drive Circuit Shorted To Battery Voltage

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