2010-2016 Ford Taurus Fuse Box: SJB vs. BJB, Programming, and Common Failures

Understanding the Two Fuse Boxes in Your Taurus

Before diagnosing any electrical issue, it's critical to know that the 2010-2016 Taurus has two distinct fuse boxes with very different functions and failure modes. Confusing them can lead to incorrect diagnoses and unnecessary parts purchases.

• Battery Junction Box (BJB): Located in the engine bay, usually near the battery. This is a robust power distribution center for high-amperage components. It is generally a simple, non-programmable unit.
• Smart Junction Box (SJB): Located inside the car, under the driver's side dashboard. 🎬 Watch: Locate your fuse boxes and OBD2 port This is a complex electronic module (also called the Body Control Module or BCM) that controls nearly all interior and body-related electrical functions. This module requires programming.

Smart Junction Box (SJB) / In-Cabin Fuse Box

The SJB is the source of many of the strange electrical problems that can plague these vehicles. Its location under the dash makes it vulnerable to water intrusion from a leaking windshield or cowl, which is the number one cause of failure.

Symptoms of a Bad SJB

• Electrical "Gremlins": The most common complaint. This can include interior lights staying on, dashboard warning lights flashing randomly, turn signals not working, power windows or locks operating on their own, and "door ajar" warnings that won't turn off.
• Parasitic Battery Drain: A classic symptom of a failing SJB. An internal relay, often the "battery saver" relay, can get stuck in the 'on' position, causing the battery to drain overnight. If your Taurus has a dead battery for no apparent reason, the SJB is a primary suspect.
• Complete Failure of a System: One or more entire systems may stop working, such as all interior lighting or all power windows.
• OBD-II Code B2276: This code may be set, indicating fewer than two remote key transmitters are programmed to the SJB, which often happens after a failed replacement attempt.

SJB Programming Requirements

This is the most critical part of replacing the SJB. The module contains vehicle-specific information known as "As-Built" data, which configures it for your car's exact options (trim level, key type, lighting, etc.). It is also linked to the Passive Anti-Theft System (PATS).

• Data Transfer: The correct procedure involves using a diagnostic scan tool to copy the As-Built data from your old SJB before removing it. This data is then downloaded into the replacement unit.
• Programming Tools: A Ford dealer's IDS scan tool can do this. Many high-end independent shops and automotive locksmiths also have tools (like Autel or Snap-on) with this capability. For the advanced DIYer, a program called FORScan, used with a compatible OBD-II adapter on a Windows laptop, can also be used to save and restore the As-Built data and perform the necessary key relearn procedures.
🎬 Watch: Step-by-step guide on using FORScan for programming
• Cloning Services: Some companies offer a mail-in service where you send both your original and a replacement (new or used) SJB, and they will clone the data from the old one to the new one, making it plug-and-play when you receive it back.

Battery Junction Box (BJB) / Under-Hood Fuse Box

The under-hood BJB is generally more reliable than the SJB, but it has one very common and well-documented point of failure: the fuel pump relay.

Known Issue: Fuel Pump Relay Failure (TSB 15-0137)

Many Ford vehicles from this era, including the Taurus platform, can experience stalling or a crank-no-start condition due to a failing internal fuel pump relay inside the BJB. The small fuse terminal for the fuel pump (often fuse #27) can overheat, melting the fuse and the terminal in the box, cutting power to the fuel pump.

• Symptoms: The engine will crank but not start. It may also stall while driving and refuse to restart. You may find a melted fuse for the fuel pump.
• The Fix: Ford issued Technical Service Bulletin (TSB) 15-0137 for this issue. The official repair does not involve replacing the entire BJB. Instead, a special kit (part number EL3Z-14293-A) is used 🎬 See how to perform the fuel pump fuse relocation to relocate the fuel pump power circuit to an unused, more robust fuse slot in the same box using an external relay and wiring harness.
• Diagnosis: If you experience a no-start condition, checking the fuel pump fuse in the BJB should be one of your first steps. If it's blown or the slot looks burnt, this TSB likely applies.

Buying a Used Fuse Box

Purchasing a used OEM fuse box can be a great way to save money, but it's essential to know what you're buying.

Inspecting a Used SJB (In-Cabin)

• Match Part Numbers EXACTLY: The engineering number on the sticker (e.g., DG1T-14290-AG) is critical. Different numbers can mean different software or hardware configurations.
• Check for Water Damage: Look for any signs of corrosion (white or green powder) on the pins and connectors. Avoid any unit that shows evidence of moisture.
• Plan for Programming: Remember, the cost of the part is not the final cost. Factor in the price of having it programmed by a dealer, locksmith, or by purchasing the tools to do it yourself.

Inspecting a Used BJB (Under-Hood)

• Check for Corrosion: Inspect all terminals for rust or corrosion, especially the main battery terminals.
• Examine the Fuel Pump Fuse Slot: Check the slot for the fuel pump fuse (typically #27) for any signs of melting or heat damage. If it's damaged, the box is still usable, but you will need to perform the TSB 15-0137 relocation fix.
• Verify Compatibility: While less complex than the SJB, it's still best to match the part number to ensure all internal relays and fuse capacities are correct for your vehicle's options.

Cost Breakdown

Prices can vary significantly based on location and supplier. Programming costs are separate from the part and labor.

Frequently Asked Questions (FAQ)