OBD Guide

B1235

Problem In The Driver Side Air Mix Control Linkage, Door, Or Motor Circuit

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$33–167 (est.)

Symptoms

  • Inability to regulate air temperature on the driver's side
  • Constant flow of only hot or only cold air
  • Rattling sounds from under the panel when the climate control is operating

Causes

  • Air mixture damper jammed
  • Damper motor malfunction
  • Open or short circuit in control circuit
  • Problems with the HVAC control unit

How to Fix

  1. Check and clean the damper mechanism from dirt and debris
  2. Test the damper motor
  3. Check the integrity of the wiring harness and connectors
  4. Measure resistance and voltage in the control circuit
  5. If necessary, replace faulty components

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