What it means
The vehicle bus reports loss of communication with smart right-front HVAC mode (vent/floor/defrost) actuator. Air distribution falls back to a default mode.
How it works
The right front mode actuator positions HVAC doors to direct air among the dash vents, floor, and defrost outlets. U065C sets when a module stops receiving expected network messages from that actuator, preventing confirmation or control of the selected right front airflow mode.
Common causes
Most likely first.
- Bus wiring open or shorted
- Module without power or ground
- Module failed
Symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
How to diagnose it
- Scan all modules for freeze-frame data and related communication faults, and confirm whether U065C is isolated to the right front mode actuator.
- Switch among vent, floor, and defrost settings and check whether airflow changes at the right front outlets or actuator data changes on the scan tool.
- Inspect the right front mode actuator connector and harness for loose terminals, corrosion, chafing, or damage at the HVAC housing.
- Check the actuator's specified fuse, power, and ground to rule out loss of electrical supply.
- Test the actuator's network wiring for opens, shorts, and poor connections to the manufacturer's specification, then use the vehicle's diagnostic procedure to assess the actuator or module.
Common fixes
- Reconnect or secure the right front mode actuator connector.
- Repair damaged wiring or corroded terminals in its network circuit.
- Restore the actuator's power or ground after correcting the supply fault.
- Replace the right front mode actuator or its module only after testing confirms an internal failure.
Can I keep driving?
Driving is generally possible if the fault only affects outlet selection, but confirm that the windshield can be kept clear. Stop if poor defrost airflow limits visibility.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.