{"nhtsa_id":10229135,"type":"service_bulletin","type_name":"Service bulletin","date_added":"2023-01-09","date":"2022-03-10","document_id":"0804322-1","mfr_campaign":null,"replaces":null,"component":"ENGINE AND ENGINE COOLING; VEHICLE SPEED CONTROL; ELECTRICAL SYSTEM","mfr_system":null,"summary":"Flash: Heating Ventilation and Air Conditioning (HVAC) Updates This bulletin involves reprogramming the HVAC module with the latest available software. Customers may experience the following:High pitch whistle coming from the dash when the blower motor is turned on.High pitch whistle originated from the defroster door when the HVAC unit in either Hi-Level (panel and defrost) or Bi-Level (panel and floor) modes. May be worsened when running the front airflow at blower bar 1-2 and rear airflow at blower bar 5-7.","document":{"url":"https://static.nhtsa.gov/odi/tsbs/2022/MC-10229135-0001.pdf","alternate_url":"https://static.nhtsa.gov/odi/tsbs/2022/MC-10229135-9999.pdf","confirmed":false},"url":"https://open.wenmarpro.com/bulletins/10229135","components":[{"id":"electrical","name":"Electrical system","parent":null},{"id":"engine","name":"Engine","parent":null},{"id":"speed-control","name":"Throttle and cruise control","parent":null}],"codes":[],"topics":[],"vehicles":[{"make":"JEEP","model":"GRAND CHEROKEE","year_from":2021,"year_to":2021,"match":"exact","vehicle_ids":["2021_jeep_grand-cherokee"]}],"as_of":"2026-10-19","note":"A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.","attribution":[]}