TRUE/FALSE: When operating the heat system, ensure all lower duct heat air nozzles are completely open. Any other configuration may cause illumination of the HEATER O/HEAT warning light.

TRUE/FALSE: When operating the heat system, ensure all lower duct heat air nozzles are completely open. Any other configuration may cause illumination of the HEATER O/HEAT warning light.

• A. True
• B. False
• C. Not required
• D. Unknown

Answer: (A)

When the heater is in use, the system relies on unrestricted airflow through the lower duct heat air nozzles. Opening them fully ensures heated air is delivered where needed and that the heater control sensors see the expected flow and temperature rise. If any lower nozzle is not completely open, airflow is restricted, which can cause the heater to act as if something is wrong—prompting the HEATER O/HEAT warning light to illuminate. The warning is tied to the heater’s ability to reach and maintain commanded heat with proper airflow; with restricted flow, the system may detect an abnormal condition and trigger the warning. So, having all lower duct heat air nozzles fully open during heat operation prevents false or erroneous warnings and ensures reliable heating. If the warning does appear, it’s a signal to verify nozzle positions and airflow in addition to other heater checks.

When the heater is in use, the system relies on unrestricted airflow through the lower duct heat air nozzles. Opening them fully ensures heated air is delivered where needed and that the heater control sensors see the expected flow and temperature rise. If any lower nozzle is not completely open, airflow is restricted, which can cause the heater to act as if something is wrong—prompting the HEATER O/HEAT warning light to illuminate. The warning is tied to the heater’s ability to reach and maintain commanded heat with proper airflow; with restricted flow, the system may detect an abnormal condition and trigger the warning. So, having all lower duct heat air nozzles fully open during heat operation prevents false or erroneous warnings and ensures reliable heating. If the warning does appear, it’s a signal to verify nozzle positions and airflow in addition to other heater checks.