NHTSA service bulletin

NHTSA Service Bulletin 10237978: 2021-2023 Ford Bronco

Official manufacturer communication context for 2021-2023 Ford Bronco, with affected products, buyer checks and links into Carchieve recall, problem and VIN research.

NHTSA service bulletin 10237978 summary graphic for 2021-2023 Ford Bronco
10237978NHTSA document ID
Manufacturer communicationcommunication type
1affected product rows
92/100quality score

Reviewed June 2026 from NHTSA manufacturer communication and service bulletin records. Carchieve is independent and not affiliated with any vehicle manufacturer or government agency.

Quick answer

Some 2021-2023 Bronco vehicles may exhibit the HVAC switching out of recirculation without input. This may be due to the air flow mode door inlet strategy while in recirculation mode. This strategy periodically purges the cabin air every 30-60 minutes depending on conditions the vehicle is operated in. If monitoring the Air Inlet Door PID with FDRS, it can go to approximately 50 % movement of the Air Inlet Door while in recirculation mode. During this climate control system strategy operation the recirculation button light should not go off. This is normal operation of the climate control system and no repairs should be attempted. If the recirculation button/light goes off then reference Workshop Manual (WSM), Section 412-00.

What this bulletin may mean before buying

Treat this as service research, not a verdict on one car. Before you buy, compare this communication with official recall campaigns, model-level owner complaint patterns, and the exact vehicle’s VIN-decoded specifications. A bulletin can help you ask a seller or dealer sharper questions about software updates, known repairs, warranty extensions and service history.

Affected products listed in this communication

MakeModelModel yearsBuyer note

Buyer checklist

  1. Run the 17-character VIN and confirm the year, make, model, engine and equipment match the listing.
  2. Check recall campaign pages for safety actions that may require dealer repair.
  3. Compare this bulletin with common problem pages for the same model and component area.
  4. Ask the seller or dealer whether the bulletin procedure, update or inspection has already been completed.
  5. Use the used-car buying checklist and get an independent inspection.

Frequently asked questions

What is NHTSA service bulletin 10237978?

Some 2021-2023 Bronco vehicles may exhibit the HVAC switching out of recirculation without input. This may be due to the air flow mode door inlet strategy while in recirculation mode. This strategy periodically purges the cabin air every 30-60 minutes depending on conditions the vehicle is operated in. If monitoring the Air Inlet Door PID with FDRS, it can go to approximately 50 % movement of the Air Inlet Door.

Is a service bulletin the same as a recall?

No. A recall is a safety campaign with a required remedy for affected VINs. A service bulletin or manufacturer communication usually describes diagnostic, repair, software, warranty or service information.

How should a used-car buyer use this bulletin?

Use it as a research signal. Compare it with recalls, owner complaints, service records, a VIN report and an independent inspection before buying.

Check the exact VIN before you buy

Model-level pages show public safety patterns. A full VIN report helps confirm the exact vehicle, decoded specs, recall applicability and buyer checks.

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