Automotive fuse box abbreviations are short labels used on fuse box covers, fuse panels, wiring diagrams, service manuals and electrical schematics to identify vehicle circuits, electrical components and control systems.
Depending on the vehicle manufacturer, the same circuit may be identified by different abbreviations. For example, a fuel pump circuit may appear as F/P, FP, FUEL PUMP or another manufacturer-specific designation.
This guide explains common Fuse Box, Fuse Panel, Fuse Block, Junction Box, Power Distribution Center and electrical circuit abbreviations used in modern vehicles.
What Is a Fuse Box?
A fuse box is an electrical distribution location containing fuses that protect vehicle circuits from excessive current.
Modern vehicles may have multiple fuse and relay locations, including an interior fuse box, underhood fuse box, junction box, power distribution center or an integrated electronic power module.
A fuse box may supply circuits for the engine, fuel system, transmission, lighting, HVAC, body electronics, safety systems and control modules.
Fuse Box vs Fuse Panel vs Fuse Block
A general term for a housing containing vehicle fuses and sometimes relays or electronic distribution components.
A panel containing fuses and circuit connections. The term is frequently used for interior fuse locations.
An assembly containing fuses, terminals and electrical distribution connections.
Common Fuse Box and Power Distribution Abbreviations
Fuse Box
Fuse Box
Fuse Panel / Fuse-related designation depending on manufacturer
Fuse Panel
Junction Box
Junction Box
Fuse Junction Box
Power Distribution Center
Power Distribution Box
Battery Junction Box
Smart Junction Box
Central Junction Box
Instrument Panel Junction Box
Passenger Junction Box
Totally Integrated Power Module
Underhood Junction Box on supported applications
Interior Fuse Box
The interior fuse box is normally located inside the passenger compartment. It may be installed under the dashboard, near the driver's side kick panel, behind a trim panel or in another interior location.
Common terminology includes I/P Fuse Box, I/P Fuse Panel, IPJB, PJB, CJB and SJB, depending on the manufacturer.
Underhood Fuse Box
The underhood fuse box is located in the engine compartment and commonly contains high-current fuses, relays and power-distribution circuits.
Common names include Underhood Fuse Box, Fuse/Relay Box, PDC, PDB, BJB and Underhood Junction Box.
What Does TIPM Mean?
TIPM stands for Totally Integrated Power Module.
TIPM is an integrated power-distribution module used on various Chrysler, Dodge, Jeep and Ram applications. Unlike a simple traditional fuse box, the module can combine fuses, relays, power distribution and electronic control functions.
Its exact functions depend on the vehicle and model year.
What Does PDC Mean?
PDC commonly means Power Distribution Center.
A PDC distributes electrical power from the battery or charging system to multiple vehicle circuits through fuses, relays and related connections.
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PDC / Fuse Box / Power Distribution
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Fuses + Relays
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Vehicle Circuits
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Electrical Loads / Control Modules
How Fuse Box Labels Are Used
A fuse-box label can identify the circuit protected by a fuse rather than the physical component itself.
For example:
- F/P may identify a fuel-pump circuit in some applications.
- INJ may identify fuel-injector circuits.
- IGN may identify ignition power.
- HORN may identify the horn circuit.
- WIPER may identify the windshield-wiper circuit.
- RR DEF may identify the rear defogger.
- ECU-B may identify battery power for an ECU on some Japanese vehicles.
The exact meaning should always be confirmed for the specific vehicle.
Japanese and Korean Fuse Box Terminology
Japanese and Korean vehicles frequently use abbreviations such as EFI, ECU-B, ECU-IG, IG1, IG2, AM1, AM2, ST, ALT, DOME, METER, TAIL and RAD FAN.
These labels can be especially useful when reading Toyota, Lexus, Honda, Nissan, Hyundai, Kia and other Asian-market wiring diagrams.
However, not every abbreviation is exclusive to Japanese or Korean vehicles. Many are also used internationally.
American and European Fuse Box Terminology
North American and European vehicles use many common electrical abbreviations such as FUSE, IGN, ECM, PCM, BCM, ABS, SRS, HVAC, A/C, PWR, DRL, FOG, STOP, PARK and ACC.
Manufacturer-specific terminology can still vary considerably.
How to Diagnose a Fuse Circuit
When a vehicle circuit protected by a fuse stops operating, the technician should not simply replace the fuse repeatedly.
- Identify the exact fuse and circuit.
- Check the vehicle wiring diagram.
- Check battery voltage.
- Inspect the fuse.
- Check voltage at the fuse.
- Check both sides of the fuse when appropriate.
- Inspect connectors and terminals.
- Check the relay or electronic control device.
- Check the circuit wiring.
- Check the load for excessive current.
- Repair the root cause.
- Verify circuit operation.
Why a Fuse Box Can Cause Diagnostic Trouble Codes
A fuse-box problem can affect engine, body, chassis and network systems.
A blown fuse supplying a control module can cause that module to stop communicating. Other modules may then store communication-related U-codes.
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Control Module Loses Power
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Module Stops Communicating
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Other Modules Detect Lost Communication
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U-Code May Be Stored
Therefore, a communication DTC does not automatically mean that the CAN network or control module is defective.
Common Fuse Box Diagnostic Mistakes
- Assuming every abbreviation has a universal meaning.
- Using a fuse diagram for the wrong model year.
- Replacing a blown fuse without finding the cause.
- Testing a fuse only by visual inspection.
- Ignoring voltage drop.
- Ignoring battery voltage.
- Ignoring ground connections.
- Replacing a control module before checking its power supply.
- Assuming every PDC or junction box has the same architecture.
- Confusing a circuit abbreviation with a component abbreviation.
- Assuming a U-code automatically means a CAN-network failure.
Recommended Diagnostic Tools
- Digital multimeter.
- Automotive test light.
- Advanced diagnostic scanner.
- Current clamp.
- Automotive oscilloscope.
- Fuse circuit tester.
- Wiring diagram.
- Manufacturer service information.
250 Automotive Fuse Box Abbreviations
The following reference contains common automotive fuse-box, relay-box and circuit abbreviations. Some are globally common, while others are manufacturer- or market-specific. Always verify the exact meaning in the vehicle documentation when an abbreviation is ambiguous.
Power, Fuse Box and Electrical Distribution
Fuse Box
Fuse Box
Fuse Panel
Fuse Panel / Fuel Pump depending on context
Junction Box
Junction Box
Fuse Junction Box
Power Distribution Center
Power Distribution Box
Battery Junction Box
Smart Junction Box
Central Junction Box
Instrument Panel Junction Box
Passenger Junction Box
Totally Integrated Power Module
Underhood Junction Box
Instrument Panel
Underhood
Battery
Battery
Battery Positive Supply
Ground
Power
Main Power Circuit
Auxiliary
Engine, Fuel Injection and Powertrain
Engine Control Module
Powertrain Control Module
Engine/Electronic Control Unit depending on application
Electronic Fuel Injection
Fuel Injector / Fuel Injection
Fuel Injection
Fuel System
Fuel Pump in many fuse-box contexts
Fuel Pump in many vehicle applications
Fuel Pump
Fuel Pressure Regulator
Electronic Throttle Control
Electronic Throttle Control System
Throttle System
Mass Air Flow Sensor/System
Manifold Absolute Pressure
Oxygen Sensor
Heated Oxygen Sensor
Air/Fuel Sensor
Air/Fuel Sensor
Crankshaft Position
Camshaft Position
Engine Coolant Temperature
Throttle Position Sensor
Intake Air Temperature
Starting and Charging System
Starter / Starting Circuit
Starter
Starter / Starting Circuit
Starter Signal / Starting Circuit
Alternator
Generator / Alternator
Charging System
Ignition Power / Ignition Circuit
Ignition
Ignition Circuit 1
Ignition Circuit 2
Ignition/Main Power Circuit on many Japanese applications
Ignition/Main Power Circuit on many Japanese applications
Accessory Power
Accessory
Starter Signal
Ignition Coil Circuit
Ignition Coil
Engine Control Module Power
ECU Battery Power on many Toyota applications
Cooling System and Engine Fans
Cooling Fan / Fan Circuit
Cooling Fan
Radiator Fan
Radiator Fan
Cooling Fan
Cooling Fan High Speed
Cooling Fan Low Speed
Radiator / Cooling System
Engine Coolant Temperature Circuit
Water Pump
HVAC, Air Conditioning and Heating
Air Conditioning
Air Conditioning
Compressor
Air Conditioning Compressor
Heater
Heater System
Blower Motor
Blower Motor
Heating, Ventilation and Air Conditioning
Heated / Heating Function
Defogger / Defrost depending on context
Defogger
Rear Defogger
Front Defrost
Positive Temperature Coefficient Heater
Lighting System
Headlamp / Headlight
Headlamp
Headlamp
Left Hand / Left Side
Right Hand / Right Side
Low Beam / Low Output depending on context
High Beam / High Output depending on context
Tail Lamps
Parking Lamps
Parking Lamp
Stop Lamps / Brake Lamps
Brake Lamp Circuit
Fog Lamps
Fog Lamp
Daytime Running Lamps
Turn Signal
Turn Signal
Hazard Lamps
Hazard Warning Lamps
Mirror Lighting
Wipers and Washer System
Windshield Wiper
Wiper
Front Wiper
Rear Wiper
Washer
Windshield Washer
Washer Pump
Wiper High Speed
Wiper Low Speed
Intermittent Wiper
Body, Doors, Windows and Seats
Power Window
Power Window
Power Window
Door Lock
Door Lock
Power Seat
Power Seat Heater
Seat Heater
Power Mirror
Power Mirror
Sunroof
Sunroof
Tailgate
Liftgate
Trunk System
Power Outlet
Cigarette Lighter / Power Outlet
Power Outlet
Dome / Interior Lighting
Interior / Room Lamp
Safety, Brake and Chassis Systems
Anti-lock Braking System
Supplemental Restraint System
Airbag System
Electric Power Steering
Electronic Parking Brake
Vehicle Stability Control on supported vehicles
Electronic Stability Control
Traction Control System
Traction Control
Brake System
Tire Pressure Monitoring System
Hill-Start / Hill-Descent Related Circuit depending on application
Vehicle Dynamic Control on supported applications
Dynamic Stability Control on supported applications
Steering Angle Sensor/System depending on context
Transmission and Drivetrain
Transmission Control Module
Transmission Control Unit
Automatic Transmission
Automatic Transmission
Transmission
Manual Transmission
Dual-Clutch Transmission
Continuously Variable Transmission
Four-Wheel Drive
All-Wheel Drive
Four-Wheel Drive
Torque Converter Clutch
Solenoid
Shift Control / Shift Solenoid Circuit
Drive/Reverse related circuit depending on application
Instrument Cluster and Interior Electronics
Instrument Cluster / Meter
Instrument Cluster
Instrument Panel / Panel Circuit
Illumination
Panel Illumination
Interior/Dome Lamp
Room/Interior Lamp
Memory Power Circuit
Radio / Audio System
Audio System
Audio, Navigation and Communication
Audio Amplifier
Navigation System
Global Positioning System
Audio/Visual System
Audio Video Navigation
USB Power / Interface
Telephone / Hands-Free System
Satellite Radio / Satellite System depending on application
Controller Area Network
Data Link Connector
Body Control and Electronic Modules
Body Control Module
Body Control Unit
Generic Electronic Module on supported Ford applications
Multiplex Integrated Control Unit on supported Honda applications
Intelligent Power Distribution Module on supported Nissan applications
Body Integrated Unit on supported applications
Electronic Time and Alarm Control System on supported Hyundai/Mitsubishi applications
Smart Junction Box
Body Control Module Power
Electronic Control Unit Power
Japanese Automotive Fuse Labels
ECU Ignition Power on many Toyota applications
ECU Battery Power on many Toyota applications
Electronic Fuel Injection Main Power
Electronic Fuel Injection
Interior/Dome Lamp
Instrument Meter/Cluster
Tail Lamp Circuit
Headlamp
Horn
Starting Circuit
Radiator Fan
Air Conditioning
Power Window
Rear Defogger
Wiper
Korean and Asian Vehicle Electrical Labels
Electronic Control Unit
Transmission Control Unit
Headlamp Leveling-related designation on supported applications
Motor Driven Power Steering on supported Hyundai/Kia applications
Ignition Circuit 1
Ignition Circuit 2
Accessory Power
Starting Circuit
Battery Power
Horn Circuit
Common Vehicle Loads and Accessories
Horn
Seat / Seat Control
Seat Heater
Mirror Heater
PTC Heater
Rear Heater / Rear Heated Circuit depending on context
Liftgate System
Tailgate
Parking Assistance System
Parking Distance Control Sensor/System
Camera System
Radar System
Advanced Driver Assistance Systems
Blind Spot Detection
Lane Departure Warning
Lane Keeping Assist
Automatic Emergency Braking
Adaptive Cruise Control or Accessory depending on context
Cruise Control System
Body Control Module
How to Identify an Unknown Fuse Abbreviation
If an abbreviation is unfamiliar, do not assume its meaning from the letters alone.
- Identify the vehicle make.
- Identify the model.
- Confirm the model year.
- Check the fuse-box cover.
- Check the owner's manual.
- Check the wiring diagram.
- Check the manufacturer's component legend.
- Identify the circuit supplied by the fuse.
- Confirm the circuit with a wiring diagram before performing repairs.
Fuse Box Abbreviation Diagnostic Flow
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Identify Vehicle + Year
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Identify Fuse Box Location
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Read Fuse Box Diagram
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Check Manufacturer Legend
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Identify Circuit
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Check Fuse Rating
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Test Power + Load + Ground
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Verify Repair
Final Takeaway
Automotive fuse box abbreviations are an important part of vehicle electrical diagnosis. They appear on fuse-box covers, wiring diagrams, service manuals and electrical distribution modules.
Common examples include FB, FP, JB, FJB, PDC, BJB, SJB, CJB, TIPM, INJ, F/P, ST, IGN, ALT, FAN, A/C, HTR, H/L, TAIL, STOP, WIPER, P/W, ABS, SRS, EPS, TPMS, ECM, PCM, BCM and many others.
Japanese and Korean vehicles can also use terms such as EFI, ECU-B, ECU-IG, IG1, IG2, AM1, AM2, DOME, METER, TAIL and RAD FAN.
Because automotive terminology is not completely standardized, the exact meaning of an abbreviation should always be confirmed using the correct vehicle-specific wiring diagram.
FAQ
What does F/P mean on a fuse box?
F/P can mean Fuel Pump or Fuse Panel depending on the vehicle and context. The fuse-box legend should be checked before interpreting it.
What does INJ mean on a fuse box?
INJ commonly refers to the fuel injector or fuel-injection circuit.
What does ST mean on a fuse box?
ST commonly refers to the starter or starting circuit, particularly in many Japanese vehicle diagrams.
What does FAN mean on a fuse box?
FAN commonly refers to a cooling fan circuit. It may be further identified as radiator fan, condenser fan or another fan depending on the vehicle.
What does IGN mean on a fuse box?
IGN commonly means ignition and identifies an ignition-switched power circuit.
What does ALT mean on a fuse box?
ALT commonly refers to the alternator or charging system.
What does ECU-B mean?
ECU-B is commonly used on some Japanese vehicles to identify battery power supplied to an ECU or related electronic control system.
What does ECU-IG mean?
ECU-IG commonly identifies ignition-switched power supplied to an ECU or electronic control circuit on supported applications.
What does AM1 and AM2 mean?
AM1 and AM2 are commonly used for main ignition or electrical power circuits on many Japanese vehicles, but their exact circuits vary by model.
What does PDC mean?
PDC commonly means Power Distribution Center.
What does TIPM mean?
TIPM stands for Totally Integrated Power Module and is used on various Chrysler, Dodge, Jeep and Ram applications.
Are fuse-box abbreviations universal?
No. The same abbreviation can have different meanings depending on the manufacturer and context.
Can a blown fuse cause a U-code?
Yes. If a fuse supplies power to a control module and the fuse opens, the module may stop communicating and other modules can store communication-related U-codes.
Should every fuse abbreviation be treated as a component name?
No. Some labels identify a component, while others identify an electrical circuit or system. For example, INJ can identify an injector circuit, while BCM identifies a control module.
Why are Japanese fuse labels different?
Japanese manufacturers commonly use electrical naming conventions such as IG1, IG2, AM1, AM2, ECU-B and ECU-IG. These labels are useful but can still vary by manufacturer and model.
Why do Korean vehicles have different fuse abbreviations?
Korean manufacturers may use their own electrical and module terminology. Some abbreviations are shared internationally, while others are manufacturer-specific.