OBD Guide
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B12B5

Blend Door Actuator Feedback Circuit Open Or Shorted To Battery Voltage

B12B5 is an OBD-II diagnostic trouble code meaning: Blend Door Actuator Feedback Circuit Open Or Shorted To Battery Voltage. Common causes: broken or damaged wiring harness, short circuit to battery voltage. Estimated repair cost: $56–167.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$56–167 (est.)

Symptoms

  • Inability to adjust the air temperature in the cabin
  • Constant supply of only hot or only cold air
  • Clicking or unusual noises from the damper area

Causes

  • Broken or damaged wiring harness
  • Short circuit to battery voltage
  • Mixer damper drive malfunction
  • Problems with the climate control unit (HVAC)

How to Fix

  1. Check the integrity of the wiring harness and contacts
  2. Check resistance and voltage in the drive circuit
  3. Replace the mixer damper drive if necessary
  4. Check and replace the climate control unit if necessary

Related codes

B12B6B12B7B12B8

FAQ

What does the B12B5 code mean?

B12B5 is an OBD-II diagnostic trouble code that indicates: Blend Door Actuator Feedback Circuit Open Or Shorted To Battery Voltage

What causes a B12B5 error code?

The most common causes of B12B5 include: Broken or damaged wiring harness; Short circuit to battery voltage; Mixer damper drive malfunction; Problems with the climate control unit (HVAC).

How do I fix a B12B5 diagnostic trouble code?

To fix B12B5: Check the integrity of the wiring harness and contacts. Check resistance and voltage in the drive circuit. Replace the mixer damper drive if necessary. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with B12B5?

Limited driving only, diagnose soon

How much does it cost to fix B12B5?

The estimated repair cost for B12B5 is $56–167. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat