2021 FORD F-150 fuse

Engine coolant reservoir. See Checking the Coolant (page 511).
G.
Windshield washer fluid reservoir.
H.
UNDER HOOD OVERVIEW - 3.3L Engine compartment fuse box.
See Fuses (page 493).
A.
Battery.
See Changing the 12V Battery (page 519).
B.
Engine oil filler cap.
See Checking the Engine Oil Level (page 510).
C.
Engine oil dipstick.
See Engine Oil Dipstick Overview (page 510).
D.
Brake fluid reservoir.
See Checking the Brake Fluid (page 309).
E.
Air filter assembly.
See Changing the Engine Air Filter (page 516).
F.
Engine coolant reservoir.
See Checking the Coolant (page 511).
G.
Windshield washer fluid reservoir.
H.
506
F-150 (TFD) Canada/United States of America, enUSA, Edition date: 202104, Second-Printing MaintenanceE337514

UNDER HOOD OVERVIEW - 3.5L ECOBOOST™
Engine compartment fuse box. See Fuses (page 493).
A.
Battery.
See Changing the 12V Battery (page 519).
B.
Engine oil filler cap.
See Checking the Engine Oil Level (page 510).
C.
Engine oil dipstick.
See Engine Oil Dipstick Overview (page 510).
D.
Brake fluid reservoir.
See Brakes (page 308).
E.
Air filter.
See Changing the Engine Air Filter (page 517).
F.
Engine coolant reservoir.
See Checking the Coolant (page 511).
G.
Windshield washer fluid reservoir.
H.
507
F-150 (TFD) Canada/United States of America, enUSA, Edition date: 202104, Second-Printing MaintenanceE313722

UNDER HOOD OVERVIEW - 3.5L, HYBRID ELECTRIC VEHICLE
(HEV)
Engine compartment fuse box. See Fuses (page 493).
A.
Battery.
See Changing the 12V Battery (page 519).
B.
Engine oil dipstick.
See Engine Oil Dipstick Overview (page 510).
C.
Engine oil filler cap.
See Adding Engine Oil (page 510).
D.
Brake fluid reservoir. See
Checking the Brake Fluid (page 309).
E.
Air filter.
See Changing the Engine Air Filter (page 517).
F.
Secondary coolant reservoir. See
Checking the Coolant (page 511).
G.
Engine coolant reservoir. See
Checking the Coolant (page 511).
H.
Windshield washer fluid reservoir.
I.
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F-150 (TFD) Canada/United States of America, enUSA, Edition date: 202104, Second-Printing MaintenanceE333718

UNDER HOOD OVERVIEW - 5.0L
Engine compartment fuse box. See Under Hood Fuse Box (page 493).
A.
Engine oil filler cap.
See Engine Oil Dipstick Overview (page 510).
B.
Engine oil dipstick.
See Engine Oil Dipstick Overview (page 510).
C.
Brake fluid reservoir.
See Checking the Brake Fluid (page 309).
D.
Air filter assembly.
See Changing the Engine Air Filter (page 517).
E.
Engine coolant reservoir.
See Checking the Coolant (page 511).
F.
Windshield washer fluid reservoir.
G.
Battery.
See Changing the 12V Battery (page 519).
H.
509
F-150 (TFD) Canada/United States of America, enUSA, Edition date: 202104, Second-Printing MaintenanceE346494

Water alone, without engine coolant, can
cause engine damage from corrosion,
overheating or freezing.
Do not use the following as a coolant
substitute, as they can cause engine
damage from overheating or freezing:
•
Alcohol.
• Methanol.
• Brine.
• Any coolant mixed with alcohol or
methanol antifreeze.
Do not add extra inhibitors or additives to
the coolant. These can be harmful and
compromise the corrosion protection of
the coolant.
Severe Climates
If you drive in extremely cold climates, you
may need to increase the coolant
concentration above 50%.
Note: A coolant concentration of 60%
provides improved freeze point protection.
Coolant concentrations above 60%
decrease the overheat protection
characteristics of the coolant and could
cause engine damage.
If you drive in extremely hot climates, you
may need to decrease the coolant
concentration to 40%.
Note: A coolant concentration of 40%
provides improved overheat protection.
Coolant concentrations below 40%
decrease the overheat and corrosion
protection characteristics of the coolant and
could cause engine damage.
Coolant Change WARNING: Do not dispose of
coolant in the household refuse or the
public sewage system. Use an authorized
waste disposal facility. Change the coolant at specific mileage
intervals. Refer to the scheduled
maintenance information. See
Normal
Scheduled Maintenance (page 667).
Note: Dispose of used coolant in the
appropriate manner.
Follow your community's regulations and
standards for recycling and disposing of
automotive fluids.
Fail-Safe Cooling
Fail-safe cooling allows you to temporarily
drive your vehicle before any incremental
component damage occurs. The fail-safe
distance depends on ambient
temperature, vehicle load and terrain.
How Fail-Safe Cooling Works If the engine begins to overheat,
the coolant temperature gauge
moves toward the red zone:
A warning lamp illuminates and
a message may appear in the
information display.
If the engine reaches a preset
over-temperature condition, the engine
automatically switches to alternating
cylinder operation. Each disabled cylinder
acts as an air pump and cools the engine.
When this occurs, your vehicle still
operates, however:
• Engine power is limited.
• The air conditioning system turns off.
Continued operation increases the engine
temperature, causing the engine to
completely shut down. Your steering and
braking effort increases in this situation.
When the engine temperature cools, you
can re-start the engine. Have your vehicle
checked as soon as possible to minimize
engine damage.
513
F-150 (TFD) Canada/United States of America, enUSA, Edition date: 202104, Second-Printing Maintenance

ENGINE AIR FILTER - INFORMATION MESSAGES - DIESEL
Action
Message
Indicates the engine air filter is performing as expected.
Filter OK
Indicates that there is a higher than expected restriction
across the engine air filter, which could represent an air filter at full useful life or a filter with an obstruction.
When this displays, inspect the engine air filter and replace if necessary.
After the inspection or engine air filter replacement, you must reset the system in order to change the status from Check Filter to Filter OK.
Check Filter See Manual
Indicates that there is an error within the electronic air filtermaintenance minder system requiring service.
System Fault See Manual
DRAINING THE FUEL FILTER
WATER TRAP - DIESEL WARNING: Do not drain the
water-in-fuel separator while the engine
is running. Failure to follow this warning
may result in fire, serious injury, death or
property damage. WARNING:
Do not dispose of fuel
in the household refuse or the public
sewage system. Use an authorized waste
disposal facility.
Your vehicle's fuel system has a fuel filter
and water separator to remove water from
the fuel.
If the water in fuel indicator illuminates
when the engine is running, stop your
vehicle as soon as safely possible, shut off
the engine, then drain the fuel and water
separator.
Note: Allowing water to stay in the fuel
system after the water in fuel indicator
illuminates could result in extensive damage
or failure of the fuel injection system. The fuel water trap is above the frame rail
under the driver side of the vehicle.
Make sure the ignition is off before
performing the following steps.
Front of Vehicle.
A
1. Loosen the drain plug approximately one and a half turns.
2. Allow the water to drain.
3. Tighten the drain plug until you feel a strong resistance.
4. Switch the ignition on for 30 seconds, then switch the ignition off. Repeat
twice.
518
F-150 (TFD) Canada/United States of America, enUSA, Edition date: 202104, Second-Printing MaintenanceE254226

WHAT ARE THE AUXILIARY
SWITCHES
The auxiliary switchboard on the overhead
console makes aftermarket customization
easier with six prewired switches
connected to the power distribution box.
Each circuit is individually fused for
connection of electrical accessories.
LOCATING THE AUXILIARY
SWITCHES
The auxiliary switchboard on the overhead
console makes aftermarket customization
easier with six prewired switches
connected to the power distribution box.
The circuits are individually fused for
connection of electrical accessories.
The switches have labels for AUX 1 through
AUX 6. They only operate when the ignition
is in the on position, whether the engine is
running or not. We recommend that you
leave the engine running to maintain
battery charge when using the switches
for an extended time or when using higher
current draw accessories. When you turn
on a switch, the indicator light on the
switch illuminates and the circuit provides
power to the device wired to that switch.
Note:
AUX switch 1 operates the off-road
lamps when your vehicle comes with this
option. LOCATING THE AUXILIARY
SWITCH WIRING
There are three sets of blunt-cut and
sealed circuits. Two sets are under the
hood and behind the battery tray, and one
set is inside your vehicle at the passenger
footwell.
The powered set (A) is taped behind the
battery tray and has a red spot tape mark.
The second set (B) is also under the hood.
It is taped behind the battery tray and has
a white spot tape mark. This set routes to
the interior passenger footwell.
Remove the battery and battery tray to
access the underhood circuits.
659
F-150 (TFD) Canada/United States of America, enUSA, Edition date: 202104, Second-Printing Auxiliary Switches - Raptor/TremorE220728 E347548 E347399

The interior set is taped on a wire harness
by the passenger side footwell. This set is
the other end of the circuits taped behind
the battery tray, with a white spot tape
mark.
Remove the fuse panel access door in the
kick panel to access the wires. If you do not
see them, you may need to pull them
down.
See Fuses (page 493). See your authorized
dealer for service.
Circuits from the under hood fuse box (A)
are powered. All other circuits (B-E) are
not connected at either end.
Additional information on fuse and relay
locations is available. See Fuses (page
493). See your authorized dealer for service.
IDENTIFYING THE AUXILIARY SWITCH WIRING
The relays are coded as follows: Fuse
Wire Size
Passenger
Footwell
Wire Color
Under-
hoodPass
Through
Wire Color
Power
Distribu- tion Box
10A
1.0 mm²
AUX 1
Violet/Green
AUX 1
Violet/Green
AUX 1
15A
1.0 mm²
AUX 2
Green/Brown
AUX 2
Green/
Brown
AUX 2
15A
1.0 mm²
AUX 3
Green/Blue
AUX 3
Green/Blue
AUX 3
10A
1.0 mm²
AUX 4
Brown
AUX 4
Brown
AUX 4
5A
1.0 mm²
AUX 5
Blue/Orange
AUX 5
Blue/Orange
AUX 5
5A
1.0 mm²
AUX 6
Yellow/
Orange
AUX 6
Yellow/
Orange
AUX 6
660
F-150 (TFD) Canada/United States of America, enUSA, Edition date: 202104, Second-Printing Auxiliary Switches - Raptor/Tremor