What does it mean?
B2429 is a Body (airbags, seat belts, body electronics) fault code. It indicates: Mirror Folding Circuit Short .
Symptoms
- Heater outlet temperature on the affected zone is wrong, usually much colder than requested
- Automatic climate control keeps hunting, changing blend and blower speed without settling
- The duct temperature reading in the climate menu is stuck at one extreme
- One zone controls correctly while the other does not
- Compressor cycling behaves oddly because the module misreads outlet temperature
Likely causes
- Shorted thermistor inside the post heater air temperature sensor
- Signal wire chafed against the heater housing bracket or a metal duct
- Condensation or coolant from a weeping heater core sitting in the sensor connector
- Loom pinched behind the centre console after heater or console work
- Corrosion bridging the signal and ground terminals inside the connector
- Sensor probe bent or pushed so that it contacts the metal housing
- Shorted input stage inside the climate control module
How to fix it
- Read the post heater sensor value and compare it with the other duct sensors while the system is completely cold
- A value pinned at one end of the scale that does not respond to warm up points to a short
- Unplug the sensor and check whether the reported value swings to the opposite extreme, which proves the harness is intact
- Measure the sensor resistance and compare it with the temperature to resistance table
- Test the signal wire to ground with both ends disconnected to locate a harness short
- Inspect the heater housing area for coolant leakage and dry or replace a contaminated connector
- Replace the sensor when it is internally shorted, then confirm both zones control correctly through a warm up