B1374 — Illuminated Entry Relay Short To Ground

How do I diagnose B1374 myself?

Start with a scan: confirm B1374, 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 B1374?

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 does OBD2 code B1374 mean?

Illuminated Entry Relay Short To Ground (B1374): a body electrical fault affecting the body electrical system. The car is usually drivable while you plan the repair. Most often caused by blown fuse or failed relay, body control module (BCM) fault, corroded or loose connectors.

What are the symptoms of B1374?

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

Will B1374 clear itself?

Sometimes B1374 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 self-diagnostic system picks up a problem with the illuminated entry circuit, it logs trouble code B1374. This code specifically points to a short to ground condition in the illuminated entry relay — meaning the electrical pathway for the dome lighting or courtesy lights has an unintended connection to the vehicle's chassis ground where it shouldn't exist. The body control module continuously watches these circuits while you drive, and when sensor readings drift outside acceptable parameters for long enough, B1374 gets stored and the check engine or body fault light illuminates on your dash.

The illuminated entry system controls the interior lights that turn on when you unlock the doors or open a door with the key in your pocket. It also manages the "theft deterrent" lighting in some applications. Since this is a body electrical issue rather than an engine or powertrain problem, the PCM won't flag drivability concerns. However, the freeze frame data saved alongside B1374 captures the exact operating conditions — engine speed, vehicle speed, coolant temperature, and electrical load — at the moment the fault occurred. That snapshot tells you whether the problem happened during a cold startup, at highway speeds, or while the vehicle was sitting with accessories running.

Common Symptoms

• Dashboard warning light remains solid or flashing depending on the fault type
• Interior dome lights fail to activate when doors are unlocked or opened
• Courtesy lights stay off when they should illuminate
• Affected lighting may flicker intermittently before failing completely
• In some vehicles, the exterior puddle lights or mirror-mounted entry lights stop working
• Power lock operation may be affected if the illuminated entry module shares circuits with the door lock system
• The malfunction typically does not impact engine performance, transmission operation, or braking systems

What Causes B1374?

The root causes range from simple connector issues to complete module failure. Technicians find that damaged wiring in high-flex areas ranks highest on the probability list.

• Corrosion or water intrusion in door jamb connectors where wires flex with every open and close cycle
• Chafed insulation on wiring running through the driver's or passenger door hinge area
• Failed illuminated entry relay or integrated circuit within the body control module
• Blown fuse protecting the interior lighting circuit
• Faulty door switch or latch assembly with integrated courtesy light contacts
• Short to ground in the wiring harness caused by aftermarket accessory installation
• Body control module internal failure affecting the relay driver circuit

How to Diagnose B1374

A systematic approach prevents unnecessary part replacements and wasted money. Follow these steps in order to isolate the fault efficiently.

1. Connect an OBD2 scanner to the vehicle's diagnostic port, retrieve all stored codes, and record the freeze frame data associated with B1374. Note the engine rpm, vehicle speed, and temperature readings when the fault first appeared — this reproduces the exact conditions needed for the code to return during verification.
2. Perform a visual inspection of the door jamb wiring harnesses, paying close attention to where wires pass through the hinges. Look for cracked insulation, broken strands, green corrosion on terminals, and loose connector locks. Flex the harness gently while watching for intermittent shorts.
3. Check all fuses related to interior lighting and the body control module. A blown fuse may indicate an overcurrent condition caused by the short to ground. Replace any blown fuses and monitor whether they blow again immediately.
4. Use a multimeter to test for continuity between the illuminated entry circuit wiring and chassis ground. A reading of zero ohms or near-zero ohms confirms the short. Trace the circuit from the BCM output toward the affected lights to narrow down the fault location.
5. Operate the door switches and lock mechanisms while monitoring live data on the scanner. Some scan tools display switch state changes that help identify whether the problem is mechanical or electrical.
6. Clear B1374 after repairs, complete a full drive cycle including conditions matching the freeze frame data, and verify the code does not return. Persistence of the fault after repair indicates an additional problem remains undetected.

Repair Options

Repair costs vary significantly depending on which component actually failed. Always start with inspection before purchasing replacement parts.

• Wiring repair or connector replacement: $80–$250
• Door switch, latch assembly, or actuator replacement: $120–$450
• Body control module repair or replacement: $300–$900

How Much Does It Cost to Fix B1374?

The total repair bill for B1374 typically falls between $80 and $900 depending on the actual fault. A wiring harness issue in the door jamb costs the least to fix, while a failed body control module requires the most expensive repair. Labor rates at independent shops generally range from $75 to $120 per hour. Most diagnostics for this code take one to two hours, and many shops include this in their repair estimate. Spending $50 to $100 on professional diagnosis before buying expensive parts almost always saves money compared to guessing and replacing components unnecessarily.

Can You Drive with B1374?

Severity: Short — Generally safe to operate in most conditions. B1374 does not affect engine operation, transmission shifting, or safety-critical systems. The main practical concerns involve visibility and security: if courtesy lights fail at night, you lose interior illumination when entering or exiting. A non-functioning illuminated entry system won't leave you stranded, but consider the security implications if central locking shares the affected circuitry and becomes unreliable. Address the fault before extended trips or severe weather when maximum visibility matters most.

Related OBD2 codes

• B1300: Power Door Lock Circuit Failure
• B1301: Power Door Lock Circuit Open
• B1302: Accessory Delay Relay Coil Circuit Failure
• B1303: Accessory Delay Relay Coil Circuit Open
• B1304: Accessory Delay Relay Coil Circuit Short To Battery
• B1305: Accessory Delay Relay Coil Circuit Short To Ground