Page 366 of 512

Black plate (28,1)Buick LaCrosse Owner Manual - 2012
10-28 Vehicle Care
Ignition Transmission
Lock Check
While parked, and with the parking
brake set, try to turn the ignition to
LOCK/OFF in each shift lever
position.
.The ignition should turn to
LOCK/OFF only when the shift
lever is in P (Park).
.With the key access ignition
system, the ignition key should
come out only in LOCK/OFF.
SeeIgnition Positions (Key
Access) on page 9‑18 orIgnition
Positions (Keyless Access) on
page 9‑20.
Contact your dealer if service is
required.
Park Brake and P (Park)
Mechanism Check
{WARNING
When you are doing this check,
the vehicle could begin to move.
You or others could be injured
and property could be damaged.
Make sure there is room in front
of the vehicle in case it begins to
roll. Be ready to apply the regular
brake at once should the vehicle
begin to move. Park on a fairly steep hill, with the
vehicle facing downhill. Keeping
your foot on the regular brake, set
the parking brake.
.To check the parking brake's
holding ability: With the engine
running and the transmission in
N (Neutral), slowly remove foot
pressure from the regular brake
pedal. Do this until the vehicle is
held by the parking brake only.
.To check the P (Park)
mechanism's holding ability:
With the engine running, shift to
P (Park). Then release the
parking brake followed by the
regular brake.
Contact your dealer if service is
required.
Page 370 of 512
Black plate (32,1)Buick LaCrosse Owner Manual - 2012
10-32 Vehicle Care
Base
Uplevel7. Locate the vertical headlamp
aiming screws, which are under
the hood near each headlamp
assembly.
8. Turn the vertical aiming screw until the headlamp beam is
aimed to the horizontal tape line.
Turn it clockwise or
counterclockwise to raise or
lower the angle of the beam.
9. Make sure that the light from the
headlamp is positioned at the
bottom edge of the horizontal
tape line. The lamp on the
left (A) shows the correct
headlamp aim. The lamp on the
right (B) shows the incorrect
headlamp aim.
10. Repeat Steps 7 through 9 for the opposite headlamp.
Page 372 of 512

Black plate (34,1)Buick LaCrosse Owner Manual - 2012
10-34 Vehicle Care
To replace one of these bulbs:
1. Open the hood. SeeHood on
page 10‑5.
A. Low-Beam Headlamp/DRL
B. High-Beam Headlamp
C. Parking/Turn Signal Lamp
2. If replacing a headlamp bulb, remove the dust cover from the
back of the headlamp housing
by turning counterclockwise
one‐quarter turn. 3. If replacing a turn signal/parking
lamp bulb on a non‐eAssist
vehicle, remove the close out
panel push pins and close out
panel covering the bulb socket.
4. Remove the bulb socket from the headlamp by turning
counterclockwise
one‐quarter turn.
5. Remove the bulb from the socket. If replacing the
high/low‐beam bulb, pry the two
clips on either end of the bulb
and pull straight out.
6. Install the new bulb in the socket. 7. Install the bulb socket by turning
clockwise one‐quarter turn.
8. If a headlamp bulb was replaced, install the dust cover in
the back of the headlamp
housing by turning clockwise
one‐quarter turn.
Uplevel Headlamp Assembly
The uplevel model vehicle has a
high intensity discharge (HID) high/
low beam, a dedicated DRL, and a
parking/turn signal lamp on the
headlamp assembly. See High
Intensity Discharge (HID) Lighting
on page 10‑33 for more information.
Page 373 of 512
Black plate (35,1)Buick LaCrosse Owner Manual - 2012
Vehicle Care 10-35
To replace one of these bulbs:
1. Open the hood. SeeHood on
page 10‑5.
A. DRL Lamp
B. Parking/Turn Signal Lamp
2. Turn the bulb socket counterclockwise to remove it
from the headlamp assembly.
3. Pull the bulb straight out from the socket. 4. Push the new bulb into the
socket and reinstall the socket
into the headlamp assembly by
turning it clockwise.
Taillamps, Turn Signal,
Stoplamps, and Back-Up
Lamps
A. Back‐Up Lamp
B. Turn Signal Lamp To replace one of these lamps:
1. Open the trunk. See
Trunk on
page 2‑13.
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 through 6 to install.
Page 374 of 512

Black plate (36,1)Buick LaCrosse Owner Manual - 2012
10-36 Vehicle Care
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. SeeTrunk on
page 2‑13 for more information.
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.
A. Bulb Socket
B. Bulb
C. Lamp Assembly
3. Turn the bulb socket (A) counterclockwise to remove it
from the lamp assembly (C).
4. Pull the bulb (B) 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
Daytime Running
Lamp (Uplevel) 3157K LCP
Front Turn Signal/
Parking Lamp 3757NAK
LCP
Headlamp High
Beam (Base) H9
Headlamp Low
Beam (Base) H11LL
License Plate Lamp W5WLL
Rear Turn Signal 3757NAK
LCP
For replacement bulbs not listed
here, contact your dealer.
Page 376 of 512

Black plate (38,1)Buick LaCrosse Owner Manual - 2012
10-38 Vehicle Care
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 on
page 10‑38, Instrument Panel Fuse
Block on page 10‑42, and Rear
Compartment Fuse Block on
page 10‑44.
Engine Compartment
Fuse Block
To remove the fuse block cover,
squeeze the three retaining clips on
the cover and lift it straight up.
Notice: Spilling liquid on any
electrical component on the
vehicle may damage it. Always
keep the covers on any electrical
component.
Page 377 of 512
Black plate (39,1)Buick LaCrosse Owner Manual - 2012
Vehicle Care 10-39
Engine Compartment Fuse Block
The vehicle may not be equipped
with all of the fuses, relays, and
features shown. J-CaseFuses Usage
6 Wiper
12 Starter J-Case
Fuses Usage
21 Rear Power
Windows
22 Sunroof
24 Front Power
Windows J-Case
Fuses Usage
25 Passive Entry/
Passive Start
Module
—Battery 2
(eAssist)
26 Antilock Brake
System Pump
27 Electric Park Brake
28 Rear Window
Defogger
41 Brake
Vacuum Pump
42 Cooling Fan K2
43 Not Used
44 Transmission
Auxiliary Oil Pump
(eAssist)
45 Cooling Fan K1
59 AIR Pump
Page 378 of 512

Black plate (40,1)Buick LaCrosse Owner Manual - 2012
10-40 Vehicle Care
Mini Fuses Usage1 Transmission
Control
Module
—Battery
2 Engine Control
Module Battery
3 Air Conditioning
Compressor Clutch
5 Engine Control
Module Run/Crank
8 Ignition
Coils
—Even (Six
Cylinder Engine),
Ignition Coils —All
(Four Cylinder
Engine
9 Ignition Coils
—Odd
(Six Cylinder
Engine)
10 Engine Control
Module
—Switched
Battery (from Engine
Control Module
Relay) Mini Fuses Usage
11 Six Cylinder Engine:
Post Catalytic
Converter Oxygen
Sensor Heater,
Mass Air Flow
Sensor, Flex Fuel
Sensor
13 Run/Crank for
Transmission
Control Module and
Fuel System Control
Module
14 Cabin Heater
Coolant Pump
(eAssist)
15 Motor Generator
Unit Coolant Pump
(eAssist)
16 Run/Crank for
eAssist Power
Inverter Module
17 Airbag
Module
—Run/
Crank Mini Fuses Usage
18 Vented Seats
(eAssist)
23 Variable Effort
Steering
(if equipped) or
eAssist Power
Inverter Module
29 Power Lumbar, Left
30 Power Lumbar,
Right or Power Pack
Cooling Fan
(eAssist)
31 Passive Entry/
Passive Start
Module
—Battery 1
(eAssist)
32 Body Control
Module 6
33 Heated
Seat
—Front
34 Antilock Brake
System Valves
35 Amplifier