B1250 on Ford: How to Diagnose & Fix
Air Temperature Internal Sensor Circuit Failure
1 Ford model · 1 documented issue · $25-$350 repair
B1250 on Ford by model: symptoms, diagnosis and fix
The temperature/blend door actuator is a very common failure on the Explorer (shared with Taurus, Flex and Lincoln MKS/MKT). The actuator's internal plastic gears strip, producing a repeated clicking or knocking sound behind the dash and leaving the cabin stuck on hot or cold, or blowing the wrong temperature on one side. On older (2002-2010) Explorers the same symptom appears on the floor/mode and blend actuators. It is an inexpensive part but the noise and inability to control cabin temperature are constant annoyances.
Common Symptoms
- Repeated clicking/knocking behind dash
- No heat or no cold air
- Different temperature left vs right
- Air won't change temperature with knob
How to Fix
Replace the failed blend door actuator. For 2011-2019 Explorer the OEM unit is Motorcraft YH-1779 (Ford AA5Z-19E616-C; aftermarket Dorman 604-234), about $25-$35; labor is short for the accessible actuator (~0.5 hr) but can be much higher if it is a deep-dash unit. Confirm the blend door itself isn't broken (door drive can shear) before/after replacement if clicking persists.
Sources for this issue (1)
B1250 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does B1250 mean on a Ford?
B1250 stands for "Air Temperature Internal Sensor Circuit Failure." Ford manufacturer-specific body code (also seen on Lincoln/Mercury and Ford-derived Mazda models). The in-cabin (interior) air temperature sensor that feeds the automatic climate control module has returned an out-of-range or missing signal. The climate control system loses the reference it uses to decide how much heat or A/C to deliver, so automatic temperature control stops regulating properly and may blow full hot or full cold. Ford's own pinpoint tests cover the sibling codes B1251 and B1253 as open- and short-to-ground faults on the same circuit, so the wiring is as suspect as the sensor itself. On Ford it is documented across 1 model: Explorer.
What are the most common causes of B1250?
The most common causes of B1250 are: Failed interior (in-car) air temperature sensor, Open, shorted, or chafed wiring in the sensor circuit, Corroded or backed-out sensor connector pins, Blocked or disconnected aspirator hose/tube feeding cabin air to the sensor (on models that use one), Faulty climate control module (EATC/HVAC head unit). The specific cause varies by vehicle.
How much does it cost to fix B1250 on a Ford?
Published repair estimates on Ford range from $25 to $350 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for B1250 on a different make?
View B1250 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.