B2347 — Mirror Switch Reference Voltage Positive Common Supply Low Voltage

B2347 — Mirror Switch Reference Voltage Positive Common Supply Low Voltage. A fault in the body electrical system. The car is usually drivable while you plan the repair. Typical causes: corroded or loose connectors, faulty switch, motor or actuator of the affected system, 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 B2347 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 B2347 does not return.

Approximate repair cost

Repair cost depends on which component actually failed. Typical scenarios for B2347 (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 B2347 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

Will B2347 clear itself?

Sometimes B2347 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.

What does OBD2 code B2347 mean?

What are the symptoms of B2347?

Drivers most often notice: the affected function (locks, windows, lighting, wipers) works intermittently or not at all, warning light on the dashboard, no impact on engine operation in most cases.

How much does it cost to fix B2347?

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.

What is the most common cause of B2347?

The most common causes are: corroded or loose connectors, faulty switch, motor or actuator of the affected system, blown fuse or failed relay.

B2347 indicates that a body control module has detected voltage in the mirror switch circuit dropping below factory specifications. The full description reads "Mirror Switch Reference Voltage Positive Common Supply Low Voltage," and it falls under the body electrical category rather than powertrain systems. When the affected module monitors this circuit and sees readings that stray outside acceptable parameters for consecutive drive cycles, it logs B2347 and triggers a warning indicator. The freeze frame data stored alongside the code captures engine speed, load, temperature, and vehicle speed at the moment the fault occurred — invaluable information for pinpointing what triggered the issue.

The body control module supplies a stable reference voltage to operate switches and actuators throughout the vehicle. That voltage feeds the mirror adjustment switch, which uses it to send position commands to the mirror motors. If moisture, corrosion, or a wiring break interrupts that reference voltage, the switch cannot communicate properly with the motors, and the module sets B2347 to flag the problem. This is a protective measure — the system shuts down the affected function rather than allowing erratic behavior that could distract the driver.

Common Symptoms of B2347

One or both mirror assemblies fail to adjust or move incompletely
Mirror adjustment works sporadically, especially in humid or wet conditions
Dashboard warning light remains illuminated after the fault occurs
Related body functions sharing the same circuit may behave erratically
Engine performance and fuel delivery remain unaffected
Mirror position memory presets may stop saving or recalling settings

Most Likely Causes

The most frequent source involves wiring damage at flex points where the door harness bends during opening and closing cycles. Moisture invasion into the mirror switch connector promotes corrosion that raises circuit resistance and pulls the reference voltage down. A blown fuse serving the mirror circuit is a straightforward and affordable fix. The mirror switch assembly itself can fail internally, though this occurs less often than wiring problems. In unusual cases, an internal fault within the body control module disrupts multiple circuits simultaneously.

How to Diagnose B2347

Connect an OBD2 scanner, verify B2347 is stored, and capture the freeze frame data — these conditions must be replicated during the repair verification process.
Scan for additional trouble codes; related codes often expose the actual root cause rather than the symptom. Check manufacturer technical service bulletins for your specific make and model, as factory-issued software updates or repair procedures frequently address B0xxx faults.
Perform a thorough visual inspection of the wiring harness and connectors feeding the body electrical system, looking for damaged insulation, greenish corrosion deposits, or pins that have backed out of their housings.
Use the scanner to monitor mirror switch and motor data PIDs while operating the adjustment controls — erratic readings confirm the fault is active.
Examine connector condition and wire integrity at high-flex areas such as door jambs and tailgate hinges, where repeated motion causes hidden wire breaks.
Clear the code, drive the vehicle through a complete cycle matching the freeze frame conditions, and verify B2347 does not reappear before returning the car to service.

Repair Options and Costs

Address the most common and least expensive failures before considering component replacement:

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

Total repair costs for B2347 typically fall between $80 and $900 depending on which component is at fault. Proper diagnosis before purchasing parts always saves money — the body control module represents the most expensive scenario and should be the final item investigated, not the first.

Can You Drive with B2347?

B2347 is generally considered safe to drive since body electrical faults rarely compromise engine operation or transmission function. The primary concerns involve visibility — non-operational mirrors reduce the driver's ability to monitor adjacent lanes — and weather conditions such as heavy rain where windshield wipers tied to the same circuit become critical. Central locking faults linked to this circuit could leave the vehicle unsecured, which warrants faster attention. For isolated mirror switch failures without additional system involvement, most drivers can continue normal operation while scheduling repair at their convenience.