B1624 — Lamp Keypad Output Open Circuit

OBD2 code B1624 flags a problem with the body electrical system (lamp keypad output open circuit). The car is usually drivable while you plan the repair. Common culprits: corroded or loose connectors, blown fuse or failed relay, body control module (BCM) fault.

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 B1624 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 B1624 does not return.

Approximate repair cost

Repair cost depends on which component actually failed. Typical scenarios for B1624 (parts and labor, USD, independent shop rates): Replace the switch or actuator: $120–$450; BCM repair or replacement: $300–$900; Repair wiring or connectors: $80–$250. Overall, fixing B1624 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 are the symptoms of B1624?

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

What is the most common cause of B1624?

The most common causes are: corroded or loose connectors, blown fuse or failed relay, body control module (BCM) fault.

How much does it cost to fix B1624?

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

Will B1624 clear itself?

Sometimes B1624 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 B1624 myself?

Start with a scan: confirm B1624, 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.

The code B1624 points to a specific problem in your vehicle's body electrical system: an open circuit condition affecting the lamp keypad output. This means the control module responsible for managing interior and exterior lighting functions has detected that it cannot properly communicate with or control the keypad illumination circuit. When the module sends a command to activate a lamp output through the keypad and receives no response, it flags this as a fault.

Body control systems oversee a wide range of convenience features — switches, motors, indicators, and lighting throughout the vehicle. Each circuit operates within specific electrical parameters. The module constantly compares actual sensor readings against factory-calibrated thresholds. When a lamp keypad output fails to register after repeated verification attempts across multiple drive cycles, the system interprets this as an open circuit and stores B1624. Most modern vehicles also capture a freeze frame snapshot alongside the code — this records engine speed, load, coolant temperature, and vehicle speed at the exact moment the fault occurred. Reviewing that data first can dramatically shorten diagnostic time by revealing whether the problem appeared during cold startup, highway cruising, or under electrical load.

Symptoms

When B1624 is present, you may notice one or more of the following:

An illuminated check-engine or body-system warning light on the dashboard
The keypad lamp fails to light when activated, or stays on continuously without responding to switches
Intermittent operation of related functions such as interior lighting, power locks, windows, or wipers
Individual switches on the keypad may feel unresponsive or produce no action
In most vehicles, engine performance and drivability remain unaffected — this code targets comfort and convenience systems, not powertrain operation

Common Causes

The most frequent reasons code B1624 sets are:

A defective switch, motor, or actuator within the affected keypad circuit — switches wear out from repeated use, and motors can seize or strip internally
Corroded, damaged, or loose electrical connectors at the keypad or module — moisture intrusion accelerates connector degradation, especially in door panels
A blown fuse or failed relay supplying power to the lamp keypad circuit — inspect the fuse box first before more involved troubleshooting
Wiring damage in high-flex areas such as door jambs, tailgate hinges, or under carpet — wires fracture from repeated bending over time
A faulty body control module itself — less common but possible if multiple body codes coexist with B1624
Water intrusion or corrosion in the keypad assembly creating an open condition

Diagnostic Steps

Follow these steps to isolate the root cause of B1624:

Connect an OBD2 scanner and confirm B1624 is stored. Record the associated freeze frame data — note the engine conditions when the fault was detected, as this guides which drive-cycle conditions to recreate during testing.
Check for any related body-system codes. Additional codes often point to the underlying cause — a failed actuator or shorted circuit may trigger several faults simultaneously.
Review manufacturer technical service bulletins for your specific make and model. Some B0xxx-series issues have documented factory fixes, software updates, or known component weaknesses.
Perform a thorough visual inspection of the wiring harness and connectors tied to the body electrical system. Look for chafed insulation, bent pins, green corrosion deposits, or disconnected plugs.
Access live data for the affected switch and motor while operating the function. Monitor whether PIDs reflect expected values — an open circuit typically shows as invalid or missing data.
Inspect wiring at flex points (door hinges, tailgate looms) and near moisture sources. Flex testing can reveal hairline fractures invisible to the eye.
Clear B1624, complete a full drive cycle including conditions from the freeze frame, then verify the code does not return.

Repair Options

Address the cheapest and most common failures before replacing expensive components:

Replace the defective switch, motor, or actuator in the affected circuit — $120–$450 depending on the part and labor
Repair or replace corroded connectors and damaged wiring harnesses — $80–$250 for most jobs
Body control module repair or replacement — $300–$900 depending on whether you choose module repair or full replacement with programming

Cost Overview

Actual repair costs for B1624 vary based on which component has failed. Parts and labor at independent shops typically break down as follows:

Switch or actuator replacement: $120–$450
Wiring harness or connector repair: $80–$250
BCM repair or replacement: $300–$900

Overall, fixing B1624 usually ranges between $80 and $900. An accurate diagnosis before purchasing parts is essential — the most expensive scenario is rarely the first place to look. Starting with visual inspections and fuse checks can rule out simple problems at no cost.

Driving Safety Verdict

B1624 carries a short-term severity rating. While your vehicle remains driveable in most cases — body electrical faults do not typically affect engine operation, transmission shifting, or braking — certain failures merit faster attention. If the code involves exterior lighting circuits, your headlights or taillights may not function properly in low visibility. Wiper motor faults become hazardous during rain or snow. Central locking issues could leave your vehicle unsecured. Address B1624 within a few days rather than indefinitely, and prioritize repairs that affect visibility or security.