What Does B1967 Mean?
This diagnostic trouble code indicates that the Body Control Module (BCM) or HVAC control module has detected a short circuit to ground in the A/C post heater sensor circuit. The post heater sensor monitors air temperature after the heater core to ensure proper cabin temperature control. The control module detected voltage levels below expected thresholds, indicating the sensor signal wire or sensor itself is shorted to vehicle ground.
Common Causes
45%
Damaged or chafed wiring harness causing short to ground between sensor and control module
30%
Failed A/C post heater temperature sensor with internal short to ground
15%
Corroded or moisture-damaged sensor connector causing short circuit
10%
Control module internal failure or faulty ground circuit
Diagnostic Steps
1
Step 1: Perform visual inspection of the A/C post heater sensor location (typically behind dash near heater core) and wiring harness for obvious damage, chafing, pinched wires, or corrosion. Check connector for moisture intrusion or damaged pins.
2
Step 2: Disconnect the A/C post heater temperature sensor connector and measure resistance between sensor ground pin and chassis ground using a digital multimeter. Should read 0-5 ohms. Then measure resistance between signal wire and ground; should read infinite (open circuit).
3
Step 3: With sensor disconnected, measure resistance of the sensor itself between signal and ground terminals. Compare to manufacturer specifications (typically 2-5k ohms at room temperature for thermistor-type sensors). If shorted (near 0 ohms), replace sensor.
4
Step 4: If sensor tests good, inspect wiring harness from sensor to control module for shorts to ground. Use multimeter in continuity mode to check signal wire to various ground points along harness route. Pay special attention to areas where harness passes through firewall or near metal brackets.
5
Step 5: Clear codes, reconnect all components, and monitor live data for proper sensor voltage (typically 0.5-4.5V depending on temperature). Cycle HVAC system through various modes and verify fault does not return.
6
Step 6: If wiring and sensor test good but code persists, suspect control module issue. Verify all ground connections to BCM/HVAC module are clean and tight before considering module replacement.
Estimated Repair Cost
$100 - $450
Parts + labor, varies by vehicle and location
This diagnostic trouble code indicates that the Body Control Module (BCM) or HVAC control module has detected a short circuit to ground in the A/C post heater sensor circuit. The post heater sensor monitors air temperature after the heater core to ensure proper cabin temperature control. The control...
The most common cause of B1967 (A/C Post Heater Sensor Circuit Short To Ground) is: Damaged or chafed wiring harness causing short to ground between sensor and control module
Typical repair costs for B1967 range from $100 to $450, depending on the vehicle, location, and whether you do it yourself or go to a shop.
This code does not present a safety risk and the vehicle is safe to drive. The only impact is potential reduced accuracy in automatic climate control temperature regulation, which may result in cabin comfort issues but does not affect vehicle operation or safety systems.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1967 to identify the root cause.
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Quick Info
Category
Body
System
HVAC Climate Control System
Difficulty
Type
Manufacturer
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