B1733 — Mirror Driver Vertical Switch Circuit Failure

B1733 — Mirror Driver Vertical Switch Circuit Failure. A fault in the body electrical system. The car is usually drivable while you plan the repair. Typical causes: damaged wiring in door jambs or wet areas, faulty switch, motor or actuator of the affected system, corroded or loose connectors.

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 B1733 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 B1733 does not return.

Approximate repair cost

Repair cost depends on which component actually failed. Typical scenarios for B1733 (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 B1733 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

What does OBD2 code B1733 mean?

How much does it cost to fix B1733?

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 are the symptoms of B1733?

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 do I diagnose B1733 myself?

Start with a scan: confirm B1733, save the freeze frame and note any companion codes. Then inspect the wiring and connectors related to the mirror driver vertical switch circuit, and verify the suspect component against live data before buying parts.

Will B1733 clear itself?

Sometimes B1733 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.

When your vehicle's body control module detects that the driver-side mirror's up-and-down adjustment circuit isn't responding correctly, it logs diagnostic trouble code B1733. This code specifically points to a "Mirror Driver Vertical Switch Circuit Failure" — meaning the electrical pathway responsible for moving your driver's mirror up or down has either shorted, opened, or is otherwise not performing within expected parameters. The mirror adjustment system falls under your car's body electrical category, which handles comfort and convenience features rather than engine management.

The body control module (BCM) doesn't trigger B1733 based on a single bad reading. It monitors the mirror switch circuit during operation and only stores the code when the fault condition appears repeatedly under specific circumstances — typically when you press the vertical adjustment button. This repeatable-failure requirement actually helps you diagnose the problem more reliably, since you can recreate the conditions that cause the code to set. The freeze frame data stored alongside B1733 captures engine load, RPM, coolant temperature, and vehicle speed at the moment of failure, giving you a precise snapshot of what was happening when the module first detected the problem.

Once B1733 is active, your dashboard may illuminate a warning light, though many vehicles won't display one immediately since body electrical codes are often stored without turning on the check engine lamp. The code itself won't affect how your engine runs, accelerates, or consumes fuel — the drivetrain remains unaffected.

Symptoms

The driver mirror fails to adjust vertically when you press the up or down switch, or moves only intermittently
Dashboard warning light may illuminate depending on your vehicle's programming
Other convenience features on the same circuit — such as window switches or additional mirror functions — may behave erratically or stop working entirely
The mirror may appear stuck in one position and won't respond to input
You won't hear the adjustment motor running when activating the vertical switch
In some cases, multiple related body codes accompany B1733, pointing toward a broader wiring issue

Common Causes

The most frequent culprit behind B1733 is wiring damage in high-flex areas — specifically the door jamb where the front door harness bends every time you open and close the door. Wires fatigue and break from repeated flexing, especially in older vehicles or those exposed to moisture.

A faulty mirror adjustment switch itself ranks among the top causes. The switch endures heavy use over the vehicle's life and can wear out internally, creating an open circuit that prevents proper signal transmission to the BCM.

Corroded or loose electrical connectors at the mirror assembly or BCM interrupt power and ground signals. Moisture intrusion accelerates connector degradation, leading to increased resistance or complete circuit opens.

A blown fuse dedicated to the mirror circuit will obviously prevent operation. While fuses rarely fail without cause, check whether the same fuse supplies other components that might be overloaded.

Worn actuator motors inside the mirror housing can fail, though this typically affects both vertical and horizontal movement rather than just one axis.

The body control module itself can develop internal faults, though this represents a less common scenario. BCM issues usually affect multiple electrical functions simultaneously.

How to Diagnose B1733

Begin by connecting an OBD2 scanner to verify that B1733 is stored in the body control module and not another system. Save any freeze frame data recorded with the code — this information reveals the exact conditions (engine load, RPM, temperature, vehicle speed) present when the fault first occurred.

Before touching any wiring, review any other trouble codes present. Codes related to other body functions or communication faults often point toward the true root cause. Check manufacturer technical service bulletins for your specific make, model, and year — many body electrical issues have documented factory fixes or software calibrations.

Perform a thorough visual inspection of the mirror adjustment circuit. Focus on the door jamb boot and hinge areas where wiring flexes constantly. Look for chafed insulation, broken strands, corroded terminals, and connectors that aren't fully seated. Press and pull on connectors while observing — intermittent contact often reveals itself under physical manipulation.

Test the mirror switch itself using a multimeter. Measure resistance across the switch terminals while actuating the vertical adjustment. Compare readings to specifications, or temporarily bypass the switch with a jumper wire to confirm the circuit responds.

Operate the switch while monitoring live data on your scan tool if it supports body control module PIDs. Watch for expected values to change when you press the adjustment button. If the BCM receives no input, the fault lies upstream; if values change but the mirror doesn't move, the problem is downstream at the motor.

Clear B1733 after your inspection, then complete a drive cycle that replicates the freeze frame conditions. Watch to see whether the code returns — a successful repair won't recur under normal operation.

Repair Options

Wiring repairs at the door jamb typically cost $80 to $250 depending on whether you need new connectors, terminal pins, or complete harness replacement. Professional labor runs one to two hours at independent shop rates.

Mirror switch replacement averages $120 to $450 in most regions. Factory switches from the dealer command higher prices than aftermarket equivalents, though aftermarket parts generally perform adequately for this application.

BCM repair through a specialist or dealer replacement runs $300 to $900. Reflashing or reprogramming existing modules costs less than full replacement when the hardware itself remains functional.

Total Cost

Your actual repair bill hinges entirely on what component fails. B1733 scenarios typically fall between $80 and $900 depending on diagnosis results. The most expensive repair — BCM replacement — should be your last resort after eliminating simpler causes. Most B1733 issues resolve with connector cleaning or switch replacement, keeping total costs well under $300 in straightforward cases.

Can You Drive with B1733?

B1733 presents minimal safety risk during normal driving — your engine, transmission, brakes, and steering remain fully operational. However, impaired mirror adjustment limits your rear visibility, creating potential hazard when changing lanes or reversing. If your mirrors serve as primary visibility aids due to restricted rear window access, address this code promptly. For most vehicles, scheduling repair within a few weeks poses no danger, but don't ignore it indefinitely if it affects your line of sight.