B1339 — Chime Input Request Circuit Short To Battery #

Note: The code label may differ depending on the vehicle manufacturer. Below are known naming variations for this DTC:

• Chime Input Request Circuit Short To Battery (Ford)
• Buzzer Request Line Shorted High (Mazda)
• Warning Chime Signal Input Circuit High (Lincoln)

Code B1339 Overview #

The B1339 OBD-II trouble code relates to the vehicle’s chime or warning buzzer system, specifically the circuit that handles requests for the chime to sound. When this code is triggered, it means the chime input request circuit—which tells your vehicle when to activate an alert chime—has an electrical short to battery voltage. In simple terms, the circuit is seeing voltage when it shouldn’t, which can confuse the system and cause false warnings or silence real alerts. While this issue doesn’t usually affect drivability, it can impact your awareness of important warnings, such as seatbelt or key-in-ignition reminders. Understanding and resolving this code helps ensure the proper function of your vehicle’s notification system and overall safety.

Frequent Symptoms for Code B1339 #

A vehicle experiencing a B1339 code often displays symptoms related to the chime or warning system. These may range from minor annoyances to more significant safety concerns. While the car’s engine and core systems are typically unaffected, drivers may notice:

• Continuous or random chime sounds, even when no warning is present
• No chime or alert when a warning condition exists (e.g., door open, seatbelt unbuckled)
• Intermittent or delayed chime activation
• Warning lights on the dashboard related to the chime/buzzer system
• Possible battery drain if the chime circuit is constantly powered

Probable Causes for Code B1339 #

The most common reasons for a B1339 code involve electrical faults within the chime input request circuit. These can originate from either the wiring, connectors, or the control modules. Here’s how the causes generally stack up:

1. Short to battery voltage in the chime input request circuit wiring (most frequent)
2. Damaged or corroded connectors at the chime request input or related modules
3. Faulty chime or buzzer module
4. Malfunctioning Body Control Module (BCM), which manages the chime signals
5. Incorrect aftermarket accessory installation (e.g., alarms, remote starters) tapping into the chime circuit

Step-by-Step Diagnosis for Code B1339 #

Proper diagnosis requires a systematic approach to avoid unnecessary part replacement and to pinpoint the actual cause. Here’s a recommended workflow:

• 1. Verify the code: Scan the vehicle using a professional OBD-II tool to confirm B1339 and check for related codes.
• 2. Inspect chime circuit wiring: Look for visible damage, chafing, or exposed wires, especially near areas where wiring harnesses pass through body panels.
• 3. Check connectors: Unplug and inspect connectors at the chime module and BCM for corrosion, bent pins, or water intrusion.
• 4. Test for voltage: With the circuit diagram, use a multimeter to check for battery voltage at the chime request input when the system should be off.
• 5. Isolate the fault: Disconnect sections of the wiring harness to determine if the short is upstream (toward the battery) or downstream (toward the module).
• 6. Inspect aftermarket installations: Check for spliced wires or accessories that might have tapped into the chime circuit.
• 7. Test or substitute the chime module: If wiring checks out, use a known-good module if available.
• 8. Consider BCM diagnosis: If no wiring or module faults are found, the Body Control Module may require further testing or replacement.

Possible Repairs for Code B1339 #

Repairing a B1339 code typically involves restoring the chime input circuit to proper condition and ensuring no stray voltage is present. Depending on what your diagnosis uncovers, the solution may include:

• Repairing or replacing damaged wiring in the chime request circuit
• Cleaning or replacing corroded connectors
• Securing or rerouting harnesses to prevent future chafing
• Removing incorrect aftermarket accessories and repairing any spliced wires
• Replacing the faulty chime/buzzer module
• Reprogramming or replacing the Body Control Module (if defective)

Is It Safe to Drive With Code B1339? #

Yes, but with limitations. Code B1339 does not directly affect engine performance or core safety systems, so your vehicle will generally drive normally. However, you may miss critical audible warnings (like seatbelt, key-in-ignition, or door-ajar alerts), which can compromise safety—especially if you rely on these reminders. For peace of mind and to maintain all safety features, prompt repair is recommended.

Vehicles Most Commonly Affected by Code B1339 #

While B1339 can appear on various makes and models, it is most frequently reported on vehicles using similar chime/buzzer control logic and networked electronics, especially from the following OEMs:

• Ford (Focus, F-150, Fusion, Taurus, Explorer)
• Lincoln (MKZ, Town Car, Navigator)
• Mazda (Mazda6, Mazda3, CX-5, Tribute)
• Mercury (Milan, Mountaineer, Grand Marquis)

Note: Some other manufacturers may use slightly different code numbers or logic, but the principle remains similar.

Frequent Mistakes & Best Practices for Code B1339 #

Diagnosing electrical faults can sometimes lead even seasoned techs down the wrong path. Here are common pitfalls and tips to avoid them:

• Replacing the chime module without testing the wiring first
• Overlooking aftermarket accessories that might have been connected to the warning circuit
• Ignoring intermittent symptoms, which may indicate a loose or chafed wire
• Skipping connector inspections, especially in wet or high-humidity climates
• Not clearing codes after repairs to confirm the issue is resolved

Quick FAQ for Code B1339 #

Still have questions? Here are answers to the most common concerns about B1339:

Q: Can B1339 be caused by a dead battery?
A: No. This code specifically refers to an overvoltage condition (short to battery) in the chime request circuit. A dead or weak battery may cause other codes, but not this one.

Q: Will disconnecting the battery clear B1339?
A: Disconnecting the battery may erase the code from memory temporarily, but if the underlying fault remains, the code will return the next time the system self-checks.

If you’re unsure, consulting a qualified technician or your OEM’s service literature is always wise.