B1253 on Ford
Air Temperature Internal Sensor Circuit Short To Ground
B1253 on Ford vehicles indicates air temperature internal sensor circuit short to ground. Au7o has documented this code across 1 Ford model — most commonly on Edge. The Electronic Automatic Temperature Control (EATC) module monitors its in-car (internal) air temperature sensor on a reference-voltage circuit. B1253 sets when the module senses an excessive voltage drop on that circuit — the signal has dropped to or near ground — indicating the sensor or its wiring is shorted to ground. Ford's companion code B1251 covers the same circuit open or shorted high. With no valid cabin temperature, automatic temperature control cannot calculate blend-door position correctly. Typical repair costs on Ford range from $180 to $650, depending on the specific model and root cause.
Common Causes of B1253
- •Failed in-car air temperature sensor (internal thermistor shorted)
- •Sensor harness chafed or pinched, shorting the signal circuit to ground
- •Corroded or water-intruded sensor connector / poor electrical connection
- •Failed Electronic Automatic Temperature Control (EATC) module
B1253 on Ford by Model
Ford Edge(1 issue)
- HVAC Temperature Blend Door Actuator Failure - Heat or A/C on One Side Only2007-2020
The plastic-geared temperature blend door actuators in the Edge's HVAC case strip their internal gears or lose their position feedback. The classic presentation is full heat on one side of the cabin and cold air on the other on a dual-zone system, or a system stuck on one temperature regardless of what the panel is set to. Most owners hear a repetitive tick/click from behind the dash near the accelerator pedal area or the center console as the actuator hunts for a position it can no longer reach. Mode and recirculation actuators fail the same way, giving defrost-only airflow or no recirc. It is frequently misdiagnosed as a plugged heater core, which produces cold air on BOTH sides rather than a split.
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What does B1253 mean on Ford?▼
B1253 stands for "Air Temperature Internal Sensor Circuit Short To Ground." The Electronic Automatic Temperature Control (EATC) module monitors its in-car (internal) air temperature sensor on a reference-voltage circuit. B1253 sets when the module senses an excessive voltage drop on that circuit — the signal has dropped to or near ground — indicating the sensor or its wiring is shorted to ground. Ford's companion code B1251 covers the same circuit open or shorted high. With no valid cabin temperature, automatic temperature control cannot calculate blend-door position correctly. On Ford specifically, this code is documented across 1 model.
What causes B1253 on Ford vehicles?▼
Common causes on Ford: Failed in-car air temperature sensor (internal thermistor shorted), Sensor harness chafed or pinched, shorting the signal circuit to ground, Corroded or water-intruded sensor connector / poor electrical connection, Failed Electronic Automatic Temperature Control (EATC) module. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix B1253 on a Ford?▼
Repair costs on Ford range from $180 to $650, depending on the specific model and root cause.
Which Ford models have B1253 documented?▼
Au7o has documented B1253 on 1 Ford model: Edge.