Guide to the 2019-2024 Hyundai Tucson Fuse Box & Smart Junction Box

Key Differences: 2019-2021 vs. 2022-2024 Tucson

The 2019-2024 model years span two distinct generations of the Hyundai Tucson, and their electrical systems, including the fuse boxes, are not interchangeable. Understanding which generation you have is the first and most important step in diagnosing issues or finding the correct replacement part.

• 2019-2021 Hyundai Tucson (Third Generation, TL Facelift): This generation uses engines like the 2.0L and 2.4L. Its fuse boxes, often called Junction Blocks, are specific to these engine types and trim options like keyless vs. keyed ignition. Part numbers for this generation often have a 'D3' prefix, such as 91950-D3400.
🎬 Watch: Locate the fuse box and OBD2 port on this generation.
• 2022-2024 Hyundai Tucson (Fourth Generation, NX4): This generation introduced new styling and powertrains, including the 2.5L gasoline engine and hybrid variants. The fuse boxes and Smart Junction Boxes were completely redesigned. Part numbers for this generation often have a 'CW' or 'N9' prefix, such as 91950-CW022 or 91950-N9060. 🎬 See this guide for 2022-2024 fuse box locations and diagrams. These models also have further distinctions based on where the vehicle was built (US or Korea).

Known Issues, Recalls, and Technical Service Bulletins (TSBs)

Hyundai has issued several recalls and TSBs related to the electrical systems of these Tucson models. While not always a direct failure of the fuse box itself, they often involve components connected to it and can present similar symptoms.

• Recall 194 (NHTSA Campaign 20V543): Affecting 2019-2021 Tucson models, this major recall addresses a fire risk originating from the Anti-Lock Brake System (ABS) module. Corrosion on the ABS module's circuit board can cause an electrical short, potentially leading to a fire even when the vehicle is turned off. Hyundai's remedy involved a new fuse to limit the current. Owners were advised to park outside and away from structures.
• Tow Hitch Harness Recall (NHTSA Campaign 23V875): This recall applies to 2022-2024 Tucsons equipped with an optional factory tow hitch wiring harness. Insufficient sealing can allow water to enter the control module, causing a short circuit that could lead to a fire or cause trailer lights to fail. The fix involves replacing the harness and module. Again, Hyundai advises owners to park outdoors until the repair is completed.
• TSB 21-01-071H: While for older Sonata models, this TSB is relevant as it shows Hyundai's use of software updates to fix issues within the Smart Junction Box (SJB). It addressed an issue where turn signals would activate in the opposite direction due to a software logic error in the SJB. This highlights that erratic behavior may be software-related.
• TSB for Display Flickering: A TSB for the 2022-2024 Tucson (NX4A) addresses the display screen flickering or going blank due to a poor connection in a coaxial cable, requiring a shield adjustment. This is an example of an electrical issue that is not related to the fuse box but can cause confusing symptoms.

Symptoms of a Failing Fuse Box or Smart Junction Box

Fuse box failures can manifest in a wide variety of ways, from simple to complex and bizarre.

• Multiple Unrelated Electrical Failures: This is the most common sign. You might experience issues like the radio not working, power windows failing, and interior lights being out all at once. This suggests a problem with a shared power distribution circuit within the junction box.
• One Specific Circuit Inoperative: If a single component (like low-beam headlights) stops working and replacing the fuse and bulb doesn't help, the fault could be in the wiring or the internal contacts of the fuse box itself.
🎬 Watch: How to test a Smart Junction Box relay.
• Erratic or Intermittent Problems: Lights flickering, gauges dropping out, or features working one moment and not the next can point to a failing SJB, a bad ground, or a loose connection. Forum users have reported strange occurrences like the passenger seat reclining on its own or the rear hatch opening randomly.
• Visible Damage or Melting: A visual inspection may reveal melted plastic around a fuse or relay socket, or signs of corrosion from water intrusion. This is a definitive sign of failure.
• No-Start or Power Loss: A major failure within the main engine compartment fuse box can cut power to critical systems like the fuel pump or engine computer, preventing the vehicle from starting.
• Parasitic Battery Drain: A stuck relay or an internal short inside the SJB can cause a continuous power draw that drains the battery when the car is off.

Programming and Immobilizer Requirements

This is a critical consideration for modern Tucsons. The interior fuse box is often a 'Smart Junction Box' (SJB) integrated with the Body Control Module (BCM).

• Does it need programming? Yes, in many cases, the SJB/BCM does. This module stores vehicle-specific information, including trim level options, key fob data, and VIN. Simply swapping the part may result in features not working correctly or the vehicle not starting.
• Is there an anti-theft link? Yes. The SJB/BCM is a key part of the immobilizer system. A mismatch between the module, keys, and engine computer can prevent the engine from starting.
• Can an independent shop program it? Sometimes. Some advanced independent shops have the tools to program or 'clone' a BCM. Cloning involves transferring the data from your original module to the replacement unit. However, for many situations, a visit to a Hyundai dealership for programming with their proprietary GDS (Global Diagnostic System) tool is required.

Buying a Used Fuse Box

Purchasing a used OEM fuse box can be a cost-effective solution, but careful verification is essential.

1. Match the Part Number EXACTLY: This is the most important rule. Do not rely on visual similarity. Find the part number on your original unit and match it to the replacement. Even a single digit difference can mean it won't work.
2. Verify Vehicle Generation and Options: Confirm the donor vehicle is the same generation (2019-2021 or 2022-2024) and has the same engine, drivetrain (AWD/FWD), and key options (keyless entry, heated seats, etc.) as your Tucson. The original warnings about 2.0L, 2.4L, and 2.5L engines are critical here.
3. Perform a Thorough Physical Inspection: Carefully inspect the used part for any signs of heat damage, melting, or warped plastic. Check all connector pins for corrosion, discoloration (from overheating), or being bent. Ensure all plastic tabs and clips are intact.
4. Consider the Source: Buy from a reputable seller who offers a warranty and can provide information about the donor vehicle.

Cost Comparison

Frequently Asked Questions (FAQ)