How many fuse boxes does a car have? (2 Key Fuse Boxes)

Electrical systems in a vehicle are responsible for powering various components and ensuring safe driving. The term known as the fuse box plays a crucial role in protecting electrical systems from overloads, and short circuits.

In this informative article, we will explore the question, ‘How many fuse boxes does a car have?’ covering the details of fuse boxes found in vehicles along with their purposes.

Let’s get started.

Are there 2 fuse boxes in a car?

The majority of vehicles are equipped with two fuse boxes: one typically known as the power distribution box, and the other as the passenger compartment fuse panel.


Other terms used for the two fuse boxes include engine compartment fuse box, and interior fuse box.

Engine Compartment Fuse Box

The engine compartment fuse box or the power distribution box is mainly located under the hood. It features high-current fuses, and is responsible for handling major electrical systems.

This fuse box contains fuse components for cooling fan, heater, trailer tow backup lamps, powertrain control module, blower motor, four-wheel drive, vehicle battery, sensor, and other important components.

To access the engine compartment fuse box, you need to open the hood of your vehicle, and locate the fuse box.

Let’s take an example of the 2023 Ford F250 Pickup truck.

The engine compartment fuse box in the 2023 Ford F250 features various fuses with specific functions as shown in the table below.

Item  Rating  Protected Component  
1  50 ACooling fan 1.  
2  50 AHeater.  
3  50 AHeater.  
4  50 AHeater.  
9  30 AFour-wheel drive module.  
10  30 ACompressed natural gas module switch.  
12  60 AAnti-lock brake system pump.  
13  30 APassenger power seat.  
14  40 AAnti-lock brake system valve.  
15  30 ABody control module RP2 bus.  
21  10 ATrailer tow backup lamps.  
22  10 AFour-wheel drive system.  
23  20 AVehicle power 1.  
24  20 AVehicle power 2 (gas).  
10 AVehicle power 2 (diesel).  
25  15 AVehicle power 3 (gas).  
10 AVehicle power 3 (diesel).  
26  20 AVehicle power 4.  
27  10 AVehicle power 5 (gas).  
20 AVehicle power 5 (diesel).  
29  15 ADiesel exhaust fluid tank heater.  
30  15 ADiesel exhaust fluid line heater.  
31  15 AGlow plug and dosing module.  
34  20 ARear heated seats.  
36  30 AElectronic power assists steering.  
37  5 A24 V alternator.  
38  10 APowertrain control module.  
Transmission control module.  
39  10 AAnti-lock brake system.  
40  10 AElectronic power assist steering.  
41  10 ABlind spot information system.  
Trailer tow tire pressure monitoring system.  
Rear electronic module controller area network.  
42  10 ASnowplow.  
43  15 AInterior power distribution box run/start.  
45  15 AHeated steering wheel.  
46  20 ANot used (spare).  
47  5 ANot used (spare).  
48  30 AAmplifier.  
49  25 ANot used (spare).  
51  40 ABlower motor.  
52  —  Not used.  
53  10 AFour-wheel drive – transfer case control module.  
54  10 ANot used (spare).  
55  10 ANot used (spare).  
56  40 AElectronic power assist steering.  
57  20 ATrailer tow lighting module.  
58  50 ACustomer interface module.  
59  60 AInverter.  
60  60 AInterior power distribution box B+.  
61  30 AVehicle battery 2.  
62  5 ASmart trailer hitch.  
63  10 ASmart data link connector.  
Enhanced central gateway.  
64  5 AGlow plug relay coil (diesel).  
65  10 ACompressed natural gas module power.  
74  30 ATrailer brake control.  
Aftermarket e-brake access.  
75  30 ACompressed natural gas powered at all times.  
76  25 ATrailer tow lighting module battery charge.  
77  30 AVehicle battery 1.  
78  20 APower point 2.  
79  20 APower point 1.  
84  20 AHorn.  
85  40 AHeated rear windshield.  
91  5 AHeadlamp control module.  
92  15 ALeft-hand headlamp.  
93  15 ARight-hand headlamp.  
94  20 APower point 3.  
95  20 APower point 4.   Smart charge module.  
98  10 ATailgate release.  
101  50 ACustomer interface module.  
102  5 ARain sensor.  
103  30 AFront wiper motor.  
105  30 AFuel pump.  
106  30 ABody control module RP1 bus.  
107  25 ATrailer tow park lamps.  
108  40 ADriver power seat.  
109  30 AStarter motor.  
111  30 APower sliding rear window.  

Passenger Compartment Fuse Panel (Interior Fuse Box)

The passenger compartment fuse panel or the interior fuse box is located in the vehicle’s dashboard or near the steering wheel. 

The process of accessing the interior fuse panel depends on the vehicle model or type.

Let’s look at an example of the 2015 Ford F350 heavy-duty truck.

The passenger compartment fuse panel in the 2015 F350 is conveniently located in the footwell area on the passenger side.

You need to remove the cover of the fuse panel by gently pulling it towards you. Once you do that, the clips of the panel will disengage allowing the panel to fall smoothly.

The interior fuse box features fuses for interior lights, power windows, power mirrors, driver seat switches, turn signals, brake lamps, headlamps, amplifiers, subwoofers, ignition switches, and so on.

The passenger compartment fuse panel of the 2015 F350 is illustrated in the table below.

Fuse or relay number  Fuse amp rating  Protected components  
1  30A  Not used (spare)  
2  15A  Auxiliary switch relay #4  
3  30A  Passenger smart window motor  
4  10A  Hood lamp  
Interior lights  
5  20A  Moonroof  
6  5A  Driver seat module  
7  7.5A  Driver lumbar motor  
Driver seat switch  
8  10A  Power mirror switch  
9  10A  Auxiliary switch relay #3  
10  10A  Customer access feed  
Run/accessory relay  
11  10A  Instrument cluster  
12  15A  Interior lighting  
Lighted running board lamps  
13  15A  Right turn signals and brake lamps  
14  15A  Left turn signals and brake lamps  
15  15A  Backup lamps, Trailer tow backup relay  
High-mounted stop lamps  
Reverse signal interior mirror  
16  10A  Right low beam headlamp  
17  10A  Left low beam headlamp  
18  10A  Brake shift interlock  
Keypad illumination  
Passive anti-theft transceiver  
Powertrain control module  
19  20A  Amplifier  
20  20A  Power door locks  
21  10A  Brake on/off switch  
22  20A  Horn  
23  15A  Not used (spare)  
24  15A  Diagnostic connector  
Electronic finish panel  
Power fold mirror relay  
Remote keyless entry  
Steering wheel control module  
25  15A  Not used (spare)  
26  5A  Steering wheel control module  
27  20A  Not used (spare)  
28  15A  Ignition switch  
29  20A  GPS module  
30  15A  Parking lamp relay  
Trailer tow parking lamp relay  
31  5A  Customer access  
Trailer brake controller (brake signal)  
32  15A  Auto dimming mirror  
Driver and passenger door lock switch illumination  
Driver and passenger smart window motor  
Moonroof motor  
Passenger window switch  
Power inverter  
Rear heated seat switch illumination  
Telescoping mirror switch  
33  10A  Restraint control module  
34  10A  Heated steering wheel module  
Rear heated seats module  
35  5A  Reverse park aid module  
Select shift switch  
Trailer brake control module  
36  10A  Fuel tank select switch  
37  10A  Positive temperature coefficient heater  
38  10A  AM/FM base radio  
39  15A  High beam headlamps  
40  10A  Parking lamps (in mirrors)  
Roof marker lamps  
41  7.5A  Passenger airbag deactivation indicator  
42  5A  Not used (spare)  
43  10A  Wiper relay  
44  10A  Auxiliary switches  
45  5A  Not used (spare)  
46  10A  Climate control  
47  15A  Fog lamps  
Fog lamp indicator (in switch)  
48  30A Circuit breaker  Power rear sliding window switch  
Power windows switch  
Moonroof switch  
49  Relay  Delayed accessory  

Basically, there are two fuse boxes in a vehicle: one for the high-current fuses, and the other for the cabin component fuses.

The location of the fuse boxes varies depending on the vehicle model, and type. However, the basic understanding is the same. The engine compartment fuse box is located under the hood while the interior fuse box is located near the driver seat.

Conclusion on ‘How many fuse boxes does a car have?’

As we come to the end of this blog, we explored two common types of fuse boxes in a vehicle including the engine compartment fuse box (power distribution box), and the interior fuse box (passenger compartment fuse panel).

We also looked at a power distribution box of the Ford F250, and the passenger compartment fuse panel of the Ford F350 pickup truck to have a clear understanding of two fuse boxes in a car.

By familiarizing yourself with the fuse box setup/fuse box diagram in your car and following the recommended maintenance practices, you can proactively address electrical issues, prevent potential breakdowns, and ultimately prolong the lifespan of your vehicle.

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