B1967 — A/C Post Heater Sensor Circuit Short To Ground

B1967 — A/C Post Heater Sensor Circuit Short To Ground. A fault in the body electrical system. The car is usually drivable while you plan the repair. Typical causes: faulty switch, motor or actuator of the affected system, body control module (BCM) fault, blown fuse or failed relay.

body electrical

Is it safe to drive?

Short-term driving is OK Usually safe to drive — body codes rarely affect drivability. Exceptions: exterior lighting and wipers in bad weather, and central locking faults that can leave the car unsecured.

How to diagnose with an OBD scanner

Read the code and freeze frame Connect an OBD2 scanner, confirm B1967 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
Check for companion codes and TSBs Related codes often reveal the real root cause. Also check manufacturer technical service bulletins (TSB) for your make and model — many B0xxx issues have factory fixes or software updates. Search by VIN on the manufacturer site or nhtsa.gov.
Inspect wiring and connectors Visually inspect the wiring harness and connectors related to the body electrical system for damage, corrosion, chafing or poor contact.
Subsystem check Operate the affected function while watching its switch and motor PIDs in live data.
Subsystem check Inspect connectors and wiring at flex points (door jambs, tailgate hinges) — wires break there first.
Verify the repair Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm B1967 does not return.

Approximate repair cost

Repair cost depends on which component actually failed. Typical scenarios for B1967 (parts and labor, USD, independent shop rates): BCM repair or replacement: $300–$900; Repair wiring or connectors: $80–$250; Replace the switch or actuator: $120–$450. Overall, fixing B1967 usually costs between $80 and $900. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.

Common questions

How much does it cost to fix B1967?

BCM repair or replacement — $300–$900; Repair wiring or connectors — $80–$250; Replace the switch or actuator — $120–$450. Exact cost depends on the root cause, your vehicle and local labor rates — a proper diagnosis is the cheapest first step.

Will B1967 clear itself?

Sometimes B1967 clears after a few drive cycles if the fault was intermittent — for example a loose connector or a tank of bad fuel. The underlying cause usually remains, so the code tends to return. Clear it once; if it comes back, diagnose rather than erase it repeatedly.

How do I diagnose B1967 myself?

Start with a scan: confirm B1967, save the freeze frame and note any companion codes. Then inspect the wiring and connectors related to the body electrical system, and verify the suspect component against live data before buying parts.

Is it safe to drive with B1967?

Usually safe to drive — body codes rarely affect drivability. Exceptions: exterior lighting and wipers in bad weather, and central locking faults that can leave the car unsecured.

What is the most common cause of B1967?

The most common causes are: faulty switch, motor or actuator of the affected system, body control module (BCM) fault, blown fuse or failed relay.

When the body control module detects that a sensor circuit has collapsed to ground reference unexpectedly, it logs code B1967. This particular fault relates to the A/C post heater temperature sensor circuit — the component responsible for monitoring air temperature after it passes through the heater core inside the HVAC plenum. When this circuit short-circuits to ground, the module can no longer read a valid temperature signal and flags the fault. Most modern vehicles use this data to modulate blend-door position and maintain consistent cabin comfort, so the issue directly affects climate control behavior rather than engine performance.

The engine control unit or body control module tracks this circuit across multiple drive cycles before confirming a hard failure. This multi-trip strategy prevents false triggers from temporary voltage fluctuations. When the module finally commits B1967 to memory, it simultaneously captures a freeze-frame snapshot — a precise record of engine RPM, calculated load, coolant temperature, and vehicle speed at the exact moment the fault occurred. That snapshot is diagnostically valuable because it reveals the operating conditions under which the problem appeared, which points you toward the root cause much faster than starting with a blank slate.

In most cases, B1967 does not create an immediate safety hazard or drivability concern. The engine continues running normally, transmission functions remain unaffected, and most of the vehicle's critical systems stay operational. However, the underlying fault can produce noticeable comfort and convenience problems depending on which specific circuit has failed.

Symptoms of B1967

The check-engine or body warning lamp illuminates on the instrument cluster
The automatic climate control system may default to a fixed ventilation mode or shut off affected functions entirely
Heater output temperature can become erratic, overly hot, or insufficiently warm
In some vehicles, the mode blend doors stop responding or freeze in one position
The A/C compressor may cycle erratically or fail to engage when needed
Affected systems tied to the same body control module can exhibit intermittent operation or go completely offline

Common Causes of B1967

Corroded or moisture-damaged connectors at the heater sensor or adjacent HVAC components
Wiring insulation worn through from vibration, heat cycling, or movement at flex points like door jambs and hinge areas
A failing body control module unable to process sensor inputs correctly
Blown fuses or faulty relays supplying power to the HVAC sensor circuit
Loose connector pins creating intermittent high-resistance connections
Short-to-ground wiring contact from damaged conduit or pinched wires behind the dashboard

How to Diagnose B1967

Connect a compatible OBD2 scanner, retrieve code B1967, and record the associated freeze-frame data. Note the engine conditions recorded at failure — these guide your inspection priorities.
Check for any manufacturer technical service bulletins applicable to your specific make, model, and model year. Some vehicles have documented software calibrations or hardware revisions that resolve recurring B1967 faults.
Perform a thorough visual inspection of the HVAC wiring harness. Focus on connectors near the firewall, instrument panel, and any harness sections that pass through flexible routing zones. Look for cracked insulation, green corrosion buildup, and signs of prior repair work.
Use the scanner's live data function to monitor the post-heater sensor voltage while wiggling the harness and connectors. A fluctuating reading confirms an intermittent short or open condition.
Test circuit continuity and ground reference at the sensor connector using a multimeter. Compare your findings against the manufacturer's specified resistance and voltage ranges.
Clear the code, then drive the vehicle through the conditions captured in the freeze frame — similar speed, load, and temperature. If B1967 returns, you have confirmed a persistent fault rather than a one-time glitch.

Repair Options and Costs

Repair costs for B1967 vary depending on which component is actually at fault. Here are typical parts-and-labor estimates from independent shops, quoted in USD:

Wiring harness repair or connector replacement: $80–$250
Body control module repair or replacement: $300–$900
Faulty switch, actuator motor, or sensor replacement: $120–$450

Diagnosing before replacing parts is essential to avoid unnecessary expense. The body control module replacement represents the highest cost scenario, yet it is rarely the culprit — wiring and connector issues account for the majority of B1967 cases. Total repair costs typically fall between $80 and $900 depending on the actual root cause and whether the repair involves harness work or full module replacement.

Can You Drive With B1967?

In most circumstances, B1967 presents no drivability risk and the vehicle remains safe to operate. The fault affects comfort systems rather than critical safety functions. However, consider the specific failure mode: if the short-to-ground condition also impacts exterior lighting circuits, wipers, or central locking through shared modules, you may face reduced visibility or security in adverse conditions. Use caution and prioritize timely repair if your vehicle exhibits any combination of lighting, locking, or weather-related system failures alongside B1967.