2021 LEXUS RX450h wiring

3606-1. Maintenance and care
WARNING
■Water in the vehicle
●Do not splash or spill liquid in the vehi-
cle, such as on the floor, in the hybrid
battery (traction battery) air vents, and
in the luggage compartment.
Doing so may cause the hybrid battery,
electrical components, etc. to mal-
function or catch fire.
●Do not get any of the SRS components
or wiring in the vehicle interior wet.
( P.30)
An electrical malfunction may cause
the airbags to deploy or not function
properly, resulting in death or serious
injury.
●Vehicles with wireless charger: Do not
let the wireless charger ( P.335) get
wet. Failure to do so may cause the
charger to become hot and cause
burns or could cause electric shock
resulting in death or serious injury.
■Cleaning the interior (especially
instrument panel)
Do not use polish wax or polish cleaner.
The instrument panel may reflect off the
windshield, obstructing the driver’s view
and leading to an accident, resulting in
death or serious injury.
NOTICE
■Cleaning detergents
●Do not use the following liquids, as
they may discolor the vehicle interior
or cause streaks or damage to painted
surfaces:
• Center Display: Organic substances such as benzine or gasoline, alkaline
solutions, and alcohol
• Seats: Alkaline solutions, organic sub- stances such as thinner or benzine,
and alcohol
• Other parts: Organic substances such as benzine or gasoline, alkaline or
acidic solutions, dye, and bleach
●Do not use polish wax or polish
cleaner. The instrument panel’s or
other interior part’s painted surface
may be damaged.
■Preventing damage to leather sur-
faces
Observe the following precautions to
avoid damage to and deterioration of
leather surfaces:
●Remove any dust or dirt from leather
surfaces immediately.
●Do not expose the vehicle to direct
sunlight for extended periods of time.
Park the vehicle in the shade, espe-
cially during summer.
●Do not place items made of vinyl, plas-
tic, or containing wax on the uphol-
stery, as they may stick to the leather
surface if the vehicle interior heats up
significantly.
■Water on the floor
Do not wash the vehicle floor with water.
Vehicle systems such as the audio system
may be damaged if water comes into
contact with electrical components such
as the audio system above or under the
floor of the vehicle. Water may also
cause the body to rust.
■When cleaning the inside of the wind-
shield
Do not allow glass cleaner to contact the
lens. Also, do not touch the lens.
(  P.214)
■Cleaning the inside of the rear win-
dow
●Do not use glass cleaner to clean the
rear window, as this may cause dam-
age to the rear window defogger
heater wires or antenna. Use a cloth
dampened with lukewarm water to
gently wipe the window clean. Wipe
the window in strokes running parallel
to the heater wires or antenna.
●Be careful not to scratch or damage
the heater wires or antenna.

3966-3. Do-it-yourself maintenance
3Remove the fuse with the pullout
tool.
Only some fuses can be removed
using the pullout tool.
4 Check if the fuse is blown.
Normal fuse
Blown fuse
Replace the blown fuse with a new fuse of
an appropriate amperage rating. The
amperage rating can be found on the fuse
box lid.
Many types of fuse are used on this vehicle.
This illustration shows a common type of
fuse used on this vehicle.
■After a fuse is replaced
●If the lights do not turn on even after the
fuse has been replaced, a bulb may need
replacement. ( P.399)
●If the replaced fuse blows again, have the
vehicle inspected by your Lexus dealer.
■If there is an overload in a circuit
The fuses are designed to blow, protecting
the wiring harness from damage.
■When replacing light bulbs
Lexus recommends that you use genuine
Lexus products designed for this vehicle.
Because certain bulbs are connected to cir-
cuits designed to prevent overload,
non-genuine parts or parts not designed for
this vehicle may be unusable.
A
B
WARNING
■To prevent system breakdowns and
vehicle fire
Observe the following precautions.
Failure to do so may cause damage to
the vehicle, and possibly a fire or injury.
●Never use a fuse of a higher amperage
rating than that indicated, or use any
other object in place of a fuse.
●Always use a genuine Lexus fuse or
equivalent.
Never replace a fuse with a wire, even
as a temporary fix.
●Do not modify the fuses or fuse boxes.
■Fuse box near the power control unit
Never check or replace the fuses as
there are high voltage parts and wiring
near the fuse box.
Doing so may cause electric shock,
resulting in death or serious injury.

4257-2. Steps to take in an emergency
7
When trouble arises
■Brake hold operated indicator
■Master warning light
■Warning buzzer
In some cases, the bu zzer may not be heard
due to being in a noisy location or audio
sound.
■Front passenger detection sensor, seat
belt reminder and warning buzzer
●If luggage is placed on the front passen-
ger seat, the front passenger detection
sensor may cause th e warning light to
flash and the warning buzzer to sound
even if a passenger is not sitting in the
seat.
●If a cushion is placed on the seat, the sen-
sor may not detect a passenger, and the
warning light may not operate properly.
■SRS warning light
This warning light system monitors the air-
bag sensor assembly, fr ont impact sensors,
side impact sensors (front door), side
impact sensors (rear), driver’s seat position
sensor, driver’s seat be lt buckle switch, front
passenger occupant cl assification system
(ECU and sensors), “AIR BAG ON” indica-
tor light, “AIR BAG OFF” indicator light,
front passenger’s seat belt buckle switch,
driver’s seat belt pretensioner, front passen-
ger’s seat belt pretensioner and force lim-
iter, airbags, interconnecting wiring and
power sources. ( P.30)
■If the malfunction indicator lamp comes
on while driving
First check the following:
●Is the fuel tank empty?
If it is, fill the fuel tank immediately.
●Is the fuel tank cap loose?
If it is, tighten it securely.
The light will go off after several driving
trips.
If the light does not go off even after several
trips, contact your Lexus dealer as soon as
possible.
■Electric power steering system warning
light (warning buzzer)
When the 12-volt battery charge becomes
insufficient or the voltage temporarily
drops, the electric power steering system
warning light may come on and the warning
buzzer may sound.
■When the tire pressure warning light
comes on
Inspect the tires to check if a tire is punc-
tured.
If a tire is punctured:  P.432
If none of the tires are punctured:
Turn the power switch off then turn it to ON
mode. Check if the tire pressure warning
light comes on or blinks.
If the tire pressure warning light blinks for
1 minute then stays on
There may be a malfunction in the tire
pressure warning system. Have the vehicle
inspected by your Lexus dealer immedi-
ately.
Warning lightDetails/Actions
(flashes)
Indicates a malfunction in the brake hold system
 Have the vehicle inspected by your Lexus dealer immediately.
Warning lightDetails/Actions
A buzzer sounds and the warning light comes on and flashes to indicate
that the master warning system has detected a malfunction.
P.428