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 A	Cooling fan 1.
2	50 A	Heater.
3	50 A	Heater.
4	50 A	Heater.
9	30 A	Four-wheel drive module.
10	30 A	Compressed natural gas module switch.
12	60 A	Anti-lock brake system pump.
13	30 A	Passenger power seat.
14	40 A	Anti-lock brake system valve.
15	30 A	Body control module RP2 bus.
21	10 A	Trailer tow backup lamps.
22	10 A	Four-wheel drive system.
23	20 A	Vehicle power 1.
24	20 A	Vehicle power 2 (gas).
	10 A	Vehicle power 2 (diesel).
25	15 A	Vehicle power 3 (gas).
	10 A	Vehicle power 3 (diesel).
26	20 A	Vehicle power 4.
27	10 A	Vehicle power 5 (gas).
	20 A	Vehicle power 5 (diesel).
29	15 A	Diesel exhaust fluid tank heater.
30	15 A	Diesel exhaust fluid line heater.
31	15 A	Glow plug and dosing module.
34	20 A	Rear heated seats.
36	30 A	Electronic power assists steering.
37	5 A	24 V alternator.
38	10 A	Powertrain control module.   Transmission control module.
39	10 A	Anti-lock brake system.
40	10 A	Electronic power assist steering.
41	10 A	Blind spot information system.   Trailer tow tire pressure monitoring system.   Rear electronic module controller area network.
42	10 A	Snowplow.
43	15 A	Interior power distribution box run/start.
45	15 A	Heated steering wheel.
46	20 A	Not used (spare).
47	5 A	Not used (spare).
48	30 A	Amplifier.
49	25 A	Not used (spare).
51	40 A	Blower motor.
52	—	Not used.
53	10 A	Four-wheel drive – transfer case control module.
54	10 A	Not used (spare).
55	10 A	Not used (spare).
56	40 A	Electronic power assist steering.
57	20 A	Trailer tow lighting module.
58	50 A	Customer interface module.
59	60 A	Inverter.
60	60 A	Interior power distribution box B+.
61	30 A	Vehicle battery 2.
62	5 A	Smart trailer hitch.
63	10 A	Smart data link connector.   Enhanced central gateway.
64	5 A	Glow plug relay coil (diesel).
65	10 A	Compressed natural gas module power.
74	30 A	Trailer brake control.   Aftermarket e-brake access.
75	30 A	Compressed natural gas powered at all times.
76	25 A	Trailer tow lighting module battery charge.
77	30 A	Vehicle battery 1.
78	20 A	Power point 2.
79	20 A	Power point 1.
84	20 A	Horn.
85	40 A	Heated rear windshield.
91	5 A	Headlamp control module.
92	15 A	Left-hand headlamp.
93	15 A	Right-hand headlamp.
94	20 A	Power point 3.
95	20 A	Power point 4.   Smart charge module.
98	10 A	Tailgate release.
101	50 A	Customer interface module.
102	5 A	Rain sensor.
103	30 A	Front wiper motor.
105	30 A	Fuel pump.
106	30 A	Body control module RP1 bus.
107	25 A	Trailer tow park lamps.
108	40 A	Driver power seat.
109	30 A	Starter motor.
111	30 A	Power 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   Subwoofer
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   Radio   SYNC
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.