B1373 — Illuminated Entry Relay Short To Battery

What are the symptoms of B1373?

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

Will B1373 clear itself?

Sometimes B1373 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 B1373 mean?

B1373 — Illuminated Entry Relay Short To Battery. 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, corroded or loose connectors, faulty switch, motor or actuator of the affected system.

What is the most common cause of B1373?

The most common causes are: damaged wiring in door jambs or wet areas, corroded or loose connectors, faulty switch, motor or actuator of the affected system.

How do I diagnose B1373 myself?

Start with a scan: confirm B1373, 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.

When your vehicle's onboard diagnostics spot something wrong with the illuminated entry circuit, it logs trouble code B1373 — a signal that the body electrical system has detected a short to battery voltage where it shouldn't exist. This code lives in the body control module or a related control unit, which constantly watches the network of switches, relays, and actuators that handle entry-related functions like power locks, interior lighting, and in some cases windows or wipers. The moment the module sees a reading that stays outside the normal range for longer than the system allows, it stores B1373 and turns on the warning light to alert you.

The entry relay covered by B1373 is part of a system that activates convenience features when you unlock the car or open a door — things like interior lights coming on, the door lock actuators responding, or related motors engaging. When a short to battery occurs, power that should flow in one direction gets redirected, creating a condition the module wasn't designed to handle. The ECU records freeze frame data alongside the code, capturing the engine speed, load, temperature, and vehicle speed at the exact moment the fault was detected. That snapshot is one of the most useful tools you have when you start diagnosing the problem, because it tells you what conditions were present when the circuit misbehaved.

Body control modules are always scanning these circuits while the vehicle runs. They expect to see specific voltage ranges and switching behavior from the illuminated entry relay and its associated components. When those expectations aren't met, the module logs the fault and marks the drive cycle. On most vehicles, B1373 won't prevent you from driving, but it will leave the affected entry functions working poorly or not at all.

Symptoms of B1373

The way B1373 shows up in everyday driving tends to involve the illuminated entry features acting up in one or more of these ways:

• Power locks respond sluggishly, work only from one switch, or stop responding entirely
• Interior lights fail to turn on or off when they should, or stay stuck on
• Window motors move slowly or refuse to move at all
• Wipers operate intermittently or fail to activate
• The check-engine or body warning light stays illuminated on the dashboard
• Affected functions sometimes work normally and then suddenly stop, indicating a circuit that's sensitive to heat or movement

What causes B1373?

Not every B1373 points to the same root cause. The fault can originate in several places along the entry circuit, and some are far more common than others. Here's the typical breakdown:

• Chafed or broken wiring, especially in door jambs — flexing wires at door hinges and tailgate seams crack over time, and moisture in those areas accelerates corrosion
• Body control module failure — the BCM itself can develop internal shorts or transistor faults that produce false B1373 codes
• Blown fuse or failed relay in the illuminated entry circuit, interrupting or misrouting power
• Faulty switch, lock motor, or actuator — any of these components can short internally and feed unwanted voltage back into the circuit
• Corroded or loose electrical connectors — oxidation at connector pins increases resistance and can cause the module to misinterpret the signal as a short
• Water intrusion into door modules or junction boxes, which is particularly common after heavy rain or vehicle washes

How to diagnose B1373

Working through B1373 methodically keeps you from replacing parts you don't need. Follow these steps in order:

1. Plug in an OBD2 scanner and confirm that B1373 is the only code stored — or note any additional codes that appear alongside it. Save the freeze frame data before clearing anything. That recorded snapshot tells you the engine rpm, load, temperature, and speed when the fault first appeared.
2. Check for related body and network codes. Codes in the B13xx range often point to the same circuit or share a common ground or power source. Also look up any factory TSBs for your specific make, model, and model year — manufacturers sometimes publish known issues and software updates that resolve codes without any hardware repair.
3. Perform a visual inspection of the wiring harness and connectors tied to the illuminated entry system. Focus on areas that move or are exposed to weather: door hinge passages, tailgate boots, and under-dash connectors. Look for frayed insulation, broken strands of wire, greenish corrosion buildup, and any connectors that are wet or loosely seated.
4. Operate the affected function while monitoring live data. Many scan tools display switch state and motor current as parameterized IDs. Watch these values change as you press the lock button or open a door. A switch that shows "active" when it shouldn't, or a motor that draws no current, narrows the problem down quickly.
5. Inspect flex points and strain reliefs where wires bend repeatedly. Door jambs, hood hinges, and trunk lid hinges are the most likely places for wires to suffer fatigue fractures that don't show obvious exterior damage.
6. Clear the code and drive the vehicle through a complete drive cycle, deliberately recreating the conditions recorded in the freeze frame data. If B1373 returns, you have confirmed an active fault and can move forward with targeted repairs.

Repair options with costs

B1373 repair costs vary significantly depending on which component is actually at fault. Prices below reflect typical parts and labor at independent shops in the United States.

• Switch or actuator replacement: $120–$450. In many cases, the lock motor, window motor, or entry switch itself is the culprit. Replacing the failed component resolves the code directly.
• Wiring or connector repair: $80–$250. When broken wires or corroded connectors are the cause, repairing the harness — either splicing in new sections or cleaning and sealing connectors — fixes the problem without touching the expensive modules.
• BCM repair or replacement: $300–$900. If the body control module is internally damaged, it may need to be repaired by a specialist or replaced outright. Module programming or relearning may be required after installation.

How much does fixing B1373 cost overall?

For most vehicles, the total bill to resolve B1373 lands somewhere between $80 and $900, with the lower end covering wiring repairs and the upper end accounting for BCM replacement. The single most important thing you can do is confirm the root cause before spending money. Most B1373 faults turn out to be simple wiring issues or failed switches, not the expensive module — so working through the cheap checks first pays off every time.

Can you drive with B1373?

In most situations, yes — B1373 is a body electrical code, and it doesn't directly affect the engine, transmission, or brakes. The car will start and drive normally. That said, if the code has disabled your exterior lights, wipers, or central locking, use extra caution. A stuck-on interior light drains the battery overnight, bad weather with nonfunctional wipers is a safety hazard, and a central locking fault can leave the vehicle unsecured. Get the code diagnosed and repaired before relying on the car in poor conditions or overnight parking.

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