Page 333 of 434

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 11/23/20
332 VEHICLE CARE
{Warning
Installation or use of fuses that do
not meet GM’s original fuse
specifications is dangerous. The
fuses could fail, and result in a fire.
You or others could be injured or
killed, and the vehicle could be
damaged.
See Accessories and Modifications
0 306 and
General Information 0305.
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.
Engine Compartment Fuse
Block
The engine compartment fuse block is
on the driver side of the engine
compartment.
Lift the fuse block cover to access the
fuses. The vehicle may not be equipped with
all of the fuses and relays shown.
Caution
Spilling liquid on any electrical
component on the vehicle may
damage it. Always keep the covers
on any electrical component.
Page 334 of 434
Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 11/23/20
VEHICLE CARE 333
FusesUsage
1 Long range radar front sensor
2 Park/Daytime running lamps
3 Exterior lighting module 4
4 Exterior lighting module 7
5 Headlamp level Fuses
Usage
6 –
7 Electronic brake control module
8 Washer pump
9 –
10 –
11 –
12 Horn Fuses
Usage
13 Front wiper
14 Exterior lighting module 6
15 Exterior lighting module 1
16 Exterior lighting module 5
17 Exterior lighting module 3
18 Aero shutter
19 –
20 –
21 Virtual key system/ Power sounder
module
22 Engine control module
23 Transmission control module/Transmission
reverse lock out
24 Active engine mount
25 –
Page 335 of 434
Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 11/23/20
334 VEHICLE CARE
FusesUsage
26 Engine control module
27 Injectors/Ignition 2
28 Charged air cooler
29 Transmission aux oil pump/Transmission
reverse lock out
30 Injectors/Ignition 1
31 Emissions 1
32 Emissions 2
33 Starter solenoid
34 –
35 –
36 Starter pinion
37 AC clutch
38 –
39 –
40 –
41 –
42 Water pump
43 – Fuses
Usage
44 –
Relays Usage
47 –
48 Front wiper speed
49 Front wiper control
51 –
52 Engine control module
53 Starter solenoid
54 Starter pinion
55 –
57 AC clutch
58 –Instrument Panel Fuse
Block
The instrument panel fuse block is in
the end of the driver side of the
instrument panel.
To access the fuses, remove the end
panel by gently prying with a plastic
tool near each clip, beginning at the
point shown.
Page 336 of 434
Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 11/23/20
VEHICLE CARE 335
To install the end cover, insert the
tabs on the back of the cover into the
slots in the instrument panel at the
points shown. Align the clips with the
slots in the instrument panel, and
press the cover into place.
The vehicle may not be equipped with
all of the fuses and relays shown.
FusesUsage
1 –
2 HVAC blower
3 –
4 –
5 Theft deterrent/ Universal garage door
opener/Overhead
console/Rain sensor Fuses
Usage
6 –
7 Air quality ionizer
8 Heated steering wheel
9 –
10 Electronic steering column lock 1
11 –
12 –
Page 337 of 434

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 11/23/20
336 VEHICLE CARE
FusesUsage
13 –
14 –
15 –
16 –
17 –
18 Display/Infotainment/ USB/Multi-function
control module
19 Airbag/ Automatic occupant sensing /
Data link connection/
Wireless charging
module/ Virtual key
module
20 Power steering column module/
Electronic steering
column lock 2
21 Driver monitor system/Performance
data recorder
22 –
23 –
24 – Fuses
Usage
25 USB
26 –
27 –
28 –
29 –
30 –
31 Headlamp level
32 –
33 Body ignition/IP ignition
34 Exhaust valve
35 Transmission control module ignition/
Engine control
module ignition/Shift
ignition/Brake
ignition
36 Shift module
37 Body control module 1/Electronic
park brake switch
38 Center stack module Fuses
Usage
39 Steering wheel controls
40 Body control module 2
41 Body control module 3
42 Body control module 4
Circuit
Breakers Usage
CB1 Auxiliary power outlet 1
CB2 Auxiliary power outlet 2
Relays Usage
1 Run after park/ Accessory
2 Run crank
3 –
4 –
5 –
Page 338 of 434
Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 11/23/20
VEHICLE CARE 337
Rear Compartment Fuse
Block
The rear compartment fuse block is
behind a cover on the driver side of
the rear compartment.
The vehicle may not be equipped with
all of the fuses, relays, and features
shown.
FusesUsage
1 Remote function actuator
2 –
3 Driver heated seat
4 Fuel tank zone module
5 –
6 –
7 –
8 –
9 –
10 Motor seat belt passenger
11 Canister vent solenoid
12 Sunroof
13 –
14 –
15 Passenger heated seat
16 –
Page 339 of 434
Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 11/23/20
338 VEHICLE CARE
FusesUsage
17 Electronic suspension control
18 –
19 Motor seat belt driver
20 Rear defog
21 DC to DC transformer 2
22 Driver power window / Door handle switch
23 External object calculating module/
Front camera
module/High
definition
localization/Short
range radar
24 Passenger power window / Door
handle switch
25 –
26 –
27 Rear drive control module
28 – Fuses
Usage
29 –
30 –
31 DC to DC transformer 1
32 Transfer case electronic control
33 Central gateway module/Side blind
zone alert
34 Video processing module
35 Hands free closure release
36 Exterior lighting module 2
37 Passenger memory seat module
38 –
39 Right front/Right rear window
40 –
41 –
42 Amplifier Fuses
Usage
43 Park assist module
44 Driver memory seat module
45 OnStar
46 –
47 –
48 –
49 –
50 Driver seat
51 Left front/Left rear window
52 Passenger seat
Relays Usage
53 –
54 –
55 Run
Page 425 of 434

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 11/23/20
424 INDEX
Distracted Driving . . . . . . . . . . . . . . . . . . 203
Dome Lamps . . . . . . . . . . . . . . . . . . . . . . . . 130
DoorAjar Light . . . . . . . . . . . . . . . . . . . . . . . . . 107
Delayed Locking . . . . . . . . . . . . . . . . . . . 17
Locks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Power Locks . . . . . . . . . . . . . . . . . . . . . . . . 17
Drive Belt Routing, Engine . . . . . . . . . 398
Drive Systems All-Wheel Drive . . . . . . . . . . . . . 236, 327
Driver
Teen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184
Driver Assistance Systems . . . . . . . . . 275
Driver Information Center (DIC) . . . . . . . . . . . . . . . . . .107, 110
Driver Mode Control . . . . . . . . . . . . . . . . 241
Driver Mode Control Light . . . . . . . . . 103
Driving
Assistance Systems . . . . . . . . . . . . . . . 283
Better Fuel Economy . . . . . . . . . . . . . 203
Characteristics andTowing Tips . . . . . . . . . . . . . . . . . . . . . 297
Competitive . . . . . . . . . . . . . . . . . . . . . . . 246
Defensive . . . . . . . . . . . . . . . . . . . . . . . . . . 204
Hill and Mountain Roads . . . . . . . . 212
If the Vehicle is Stuck . . . . . . . . . . . . 214
Impaired . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
Loss of Control . . . . . . . . . . . . . . . . . . . . 206 Driving (cont'd)
Off-Road Recovery . . . . . . . . . . . . . . . . 206
Track Events and
Competitive . . . . . . . . . . . . . . . . . . . . . . 207
Vehicle Load Limits . . . . . . . . . . . . . . 214
Wet Roads . . . . . . . . . . . . . . . . . . . . . . . . . 211
Winter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213
Dual Automatic Climate Control System . . . . . . . . . . . . . . . . . . . . 196
E
Electric Brake Boost . . . . . . . . . . . . . . . . 236
Electric Parking Brake . . . . . . . . . . . . . . 237
Electric Parking Brake Light . . . . . . . 100
Electrical Equipment, Add-On . . . . . 303
Electrical SystemEngine Compartment Fuse
Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 332
Fuses and Circuit Breakers . . . . . . . 331
Instrument Panel Fuse Block . . . . 334
Overload . . . . . . . . . . . . . . . . . . . . . . . . . . . 330
Rear Compartment Fuse Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 337
Emergency OnStar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 414
Engine
Air Cleaner/Filter . . . . . . . . . . . . . . . . . 316 Engine (cont'd)
Check Light (Malfunction
Indicator) . . . . . . . . . . . . . . . . . . . . . . . . . 97
Compartment Overview . . . . . . . . . . 309
Coolant Temperature Gauge . . . . . . . . . . . . . . . . . . . . . . . . . 94, 95
Coolant Temperature
Warning Light . . . . . . . . . . . . . . . . . . . 103
Cooling System . . . . . . . . . . . . . . . . . . . 317
Drive Belt Routing . . . . . . . . . . . . . . . . 398
Exhaust . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226
Heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222
Oil Life System . . . . . . . . . . . . . . . . . . . . 314
Oil Pressure Light . . . . . . . . . . . . . . . . . 104
Overheating . . . . . . . . . . . . . . . . . . . . . . . 322
Power Messages . . . . . . . . . . . . . . . . . . 117
Running While Parked . . . . . . . . . . . 227
Starting . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220
Engine Air Filter Life System . . . . . . 315
Entry Lighting . . . . . . . . . . . . . . . . . . . . . . 131
Equipment, Towing . . . . . . . . . . . . . . . . . 302
Event Data Recorders . . . . . . . . . . . . . . 411
Exit Lighting . . . . . . . . . . . . . . . . . . . . . . . . 132
Extended Parking . . . . . . . . . . . . . . . . . . . 226
Extender, Seat Belt . . . . . . . . . . . . . . . . . . 46
Exterior Lamp Controls . . . . . . . . . . . . 126
Exterior Lamps Off Reminder . . . . . . 128
Exterior Lighting Battery Saver . . . . 133