Page 257 of 367
Buick LaCrosse Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
9159288) - 2016 - CRC - 10/5/15
256 Vehicle Care
Taillamps, Turn Signal,
Stoplamps, and Back-Up
Lamps
1. Back-Up Lamp
2. Turn Signal Lamp
To replace one of these lamps:1. Open the trunk. See Trunk 038.
2. Remove the fasteners and pull back the trunk trim.
3. Remove the four plastic wing nuts holding the taillamp
assembly in place. 4. Pull out the taillamp assembly
and disconnect the wiring
harness.
5. Turn the bulb socket counterclockwise to remove it.
6. Pull the old bulb straight out of the bulb socket.
7. Reverse Steps 1–6 to install.
License Plate Lamp
The license plate lamps for this
vehicle are on the trunk lid.
To replace one of these bulbs: 1. Open the trunk. See Trunk 038.2. Push the end on either of the
lamp assemblies (passenger
side shown) and then move the
lamp assembly down to
remove it from the trunk lid.
Page 258 of 367

Buick LaCrosse Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
9159288) - 2016 - CRC - 10/5/15
Vehicle Care 257
3. Turn the bulb socket (1)counterclockwise to remove it
from the lamp assembly (3).
4. Pull the bulb (2) straight out of the bulb socket.
5. Push the replacement bulb straight into the bulb socket
and turn the bulb socket
clockwise to install it into the
lamp assembly.
6. Move the lamp assembly into the trunk lid, engaging the clip
side first.
7. Push on the lamp side opposite the clip until the lamp assembly
snaps into place.
Replacement Bulbs
Exterior Lamp Bulb
Number
Back-Up Lamp 921LL (W16W)
Front Turn
Signal Lamp 7444NA
Headlamp High
Beam (Base) HIR2
Headlamp Low
Beam (Base) HIR2
License Plate Lamp W5WLL
Rear Turn Signal 7443NA (WY21W)
For replacement bulbs not listed
here, contact your dealer.
Electrical System
High Voltage Devices and
Wiring
{Warning
Exposure to high voltage can
cause shock, burns, and even
death. The high voltage
components in the vehicle can
only be serviced by technicians
with special training.
High voltage components are
identified by labels. Do not
remove, open, take apart,
or modify these components.
High voltage cable or wiring has
orange covering or labels. Do not
probe, tamper with, cut, or modify
high voltage cable or wiring.
Electrical System
Overload
The vehicle has fuses and circuit
breakers to protect against an
electrical system overload.
Page 259 of 367

Buick LaCrosse Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
9159288) - 2016 - CRC - 10/5/15
258 Vehicle Care
When the current electrical load is
too heavy, the circuit breaker opens
and closes, protecting the circuit
until the current load returns to
normal or the problem is fixed. This
greatly reduces the chance of circuit
overload and fire caused by
electrical problems.
Fuses and circuit breakers protect
power devices in the vehicle.
Replace a bad fuse with a new one
of the identical size and rating.
If there is a problem on the road and
a fuse needs to be replaced, the
same amperage fuse can be
borrowed. Choose some feature of
the vehicle that is not needed to use
and replace it as soon as possible.
Headlamp Wiring
An electrical overload may cause
the lamps to go on and off, or in
some cases to remain off. Have the
headlamp wiring checked right away
if the lamps go on and off or
remain off.
Windshield Wipers
If the wiper motor overheats due to
heavy snow or ice, the windshield
wipers will stop until the motor cools
and will then restart.
Although the circuit is protected
from electrical overload, overload
due to heavy snow or ice may
cause wiper linkage damage.
Always clear ice and heavy snow
from the windshield before using the
windshield wipers.
If the overload is caused by an
electrical problem and not snow or
ice, be sure to get it fixed.
Fuses and Circuit
Breakers
The wiring circuits in the vehicle are
protected from short circuits by a
combination of fuses and circuit
breakers. This greatly reduces the
chance of damage caused by
electrical problems.To check a fuse, look at the
silver-colored band inside the fuse.
If the band is broken or melted,
replace the fuse. Be sure to replace
a bad fuse with a new one of the
identical size and rating.
Fuses of the same amperage can
be temporarily borrowed from
another fuse location, if a fuse goes
out. Replace the fuse as soon as
possible.
To identify and check fuses, circuit
breakers, and relays, see
Engine
Compartment Fuse Block 0259 and
Instrument Panel Fuse Block 0262.
Page 260 of 367
Buick LaCrosse Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
9159288) - 2016 - CRC - 10/5/15
Vehicle Care 259
Engine Compartment
Fuse Block
To remove the fuse block cover,
squeeze the three retaining clips on
the cover and lift it straight up.
Caution
Spilling liquid on any electrical
component on the vehicle may
damage it. Always keep the
covers on any electrical
component.
The vehicle may not be equipped
with all of the fuses, relays, and
features shown.Fuses Usage
1 Transmission control module–battery
2 Engine control module battery
3 A/C clutch Fuses Usage
5 Engine control module/Run/Crank
6 Wiper
7 Long range radar/ Front camera
8 Ignition coils–even (6–cylinder engine)/
Ignition coils–all
(4–cylinder engine)
Page 261 of 367

Buick LaCrosse Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
9159288) - 2016 - CRC - 10/5/15
260 Vehicle Care
FusesUsage
9 Ignition coils–odd (6–cylinder engine)
10 Engine control module–switched
battery
11 6–cylinder Engine: post catalytic
converter/O2 sensor/
Heater/Mass air flow
sensor/FlexFuel
sensor/Secondary
air induction
solenoid
12 Starter
13 Crank for transmission control
module/Fuel pump
power/Chassis
control module
(eAssist)
14 Cabin heater coolant pump (eAssist)/
secondary air
injector/Secondary
air injector with
pressure sensor Fuses
Usage
15 Motor generator unit coolant pump
(eAssist)
16 Run/Crank for eAssist power
inverter module
17 –
18 Sunshade module/ Vehicle air
purification system/
Ventilated seats
20 Heated steering wheel (non eAssist)
21 Rear power windows
22 Sunroof
23 Variable effort steering (if
equipped) or eAssist
power inverter
module
24 Front power windows
25 Rear heated seats Fuses
Usage
26 Antilock brake system pump
27 Electric parking brake
28 Rear window defogger
29 Heated seat/Left power lumbar
30 Heated Seat/Right power pack cooling
fan (eAssist)
31 AWD/Electronic suspension control
32 Body control module 6
33 Memory seat–front
34 Antilock brake system valves
35 Amplifier
36 Adaptive forward lighting (AFL)
motors–battery
37 Right high-beam
Page 262 of 367

Buick LaCrosse Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
9159288) - 2016 - CRC - 10/6/15
Vehicle Care 261
FusesUsage
38 Left high-beam
41 Brake vacuum pump
42 Cooling fan K2
43 –
44 Transmission auxiliary oil pump
(eAssist)
45 Cooling fan K1
46 Cooling fan relay
47 6–cylinder engine: Pre-catalytic
converter O2 sensor
heater/Canister
purge solenoid.
4–cylinder engine:
Pre and post
catalytic converter
O2 sensor Heaters/
Canister purge
solenoid
48 Fog lamps
49 Right HID headlamp
50 Left HID headlamp
51 Horn Fuses
Usage
52 Cluster Run/Crank
53 Run/Crank for: rearview mirror/Rear
vision camera/Air
quality sensor/Aero
shutter motor
54 Run/Crank for: HVAC/Headlamp
switch
55 Outside rearview mirror/Universal
remote system/Front
window switches
56 Windshield washer
59 AIR pump
60 Heated mirror
62 Canister vent
64 Adaptive forward lighting (AFL)
module–battery
65 –
66 AIR solenoid (eAssist) Fuses
Usage
67 Fuel pump power module/Chassis
control module
69 Regulated voltage control sensor
70 Parking assist/Side blind zone
71 Passive entry/ Passive start
Relays Usage
1 A/C Clutch
2 Starter
4 Wiper speed
5 Wiper control
6 Cabin heater coolant pump (eAssist)/
Secondary air
injector/Secondary
air injector with
pressure sensor
7 Engine control module
9 Cooling fan
Page 263 of 367
Buick LaCrosse Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
9159288) - 2016 - CRC - 10/5/15
262 Vehicle Care
RelaysUsage
10 Cooling fan 11 Transmission auxiliary oil pump
(eAssist)
13 Cooling fan
14 Headlamp low-beam
15 Run/Crank
16 AIR pump
17 Rear window defoggerInstrument Panel Fuse
Block
The instrument panel fuse block is
located in the instrument panel, on
the driver side of the vehicle. To
access the fuses, open the fuse
panel door by pulling down at
the top.
Press in on the sides of the door to
release it from the instrument panel.
Pull the door toward you to release
it from the hinge.
Page 264 of 367

Buick LaCrosse Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
9159288) - 2016 - CRC - 10/5/15
Vehicle Care 263
The vehicle may not be equipped
with all of the fuses, relays, and
features shown.Fuses Usage
1 APO 3
2 Body control module 7
3 Steering wheel controls backlight
4 Radio/Human machine interface/
Rear auxiliary audio
jack/Front auxiliary
audio video jack/
Touchpad/Remote
media player/Bluray
remote media player
5 OnStar/Universal hands–free phone
6 Power outlet 1
7 Power outlet 2
8 Body control module 1
9 Body control module 4 Fuses Usage
10 Body control module 8
11 Front HVAC/Blower
12 Passenger seat
13 Driver seat
14 Diagnostic link connector
15 Airbag/Automatic occupant sensing
16 Trunk
17 HVAC Controller
18 Pre-fuse for fuses 4 and 5
19 Center stack displays/Head-up
display/Right
steering wheel
control switch/Rear
seat infotainment
display (eAssist)/
HVAC/Center stack
displays Fuses Usage
20 Rear seat entertainment
display/Rear seat
audio
21 Instrument cluster
22 Discrete logic ignition switch
23 Body control module 3
24 Body control module 2
25 Rear HVAC/Blower
26 AC DC inverter
Relays Usage R1 Trunk relay
R2 –
R3 Power outlet relay