Learn about Cadillac CT4 2020-2024 fuse box and relay’s locations, functions, and maintenance tips for optimal vehicle electrical system.

The Cadillac CT4 (2020-2024) is a luxury compact sedan that combines sporty performance with elegant design. Available in several trims, including the high-performance CT4-V, the CT4 offers a dynamic driving experience with a sleek, aerodynamic body style. Its compact yet refined profile is designed for agility and comfort, appealing to those who want luxury in a smaller form factor.

To support its advanced technology and comfort features, the CT4 relies on an efficient electrical system controlled by fuse boxes and relays. The primary fuse box is located under the hood near the engine, while an additional fuse panel is situated within the cabin, typically near the driver’s side. Relays, which manage high-power components like the ignition and cooling systems, are housed near these fuse boxes. Routine maintenance of the fuse boxes and relays is essential for the reliable operation of the CT4’s electronic systems.

MUST READ: DYI – How to Check Car Fuses?

(2020-2024) Cadillac CT4 fuse box and relay with Diagram

WARNING

  • Never replace a fuse with one that has a higher amperage rating.
  • A fuse with a too-high amperage could damage the electrical part and cause a fire.
  • On no account should fuses be repaired (e.g. patched up with tin foil or wire) as this may cause serious damage elsewhere in the electrical circuit or cause a fire.
  • If a fuse blows repeatedly, do not keep replacing it. Instead, have the cause for the repeated short circuit or overload tracked and fixed.
  • Terminal and harness assignments for individual connectors will vary depending on vehicle equipment level, model, and market.

Cadillac CT4 2020-2024 fuse assignment

Cadillac CT4 Year of production: 2020, 2021, 2022, 2023, 2024

Location of Fuse Boxes

Cadillac CT4 (2020-2024): Engine compartment fuse box location

Engine Compartment Fuse Block:
The engine compartment fuse block is on the passenger side of the engine compartment. Lift the fuse block cover to access the fuses.

Cadillac CT4 (2020-2024): Instrument panel fuse box location

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.

Cadillac CT4 (2020-2024): Rear compartment fuse box location

Rear Compartment Fuse Block:
The rear compartment fuse block is behind a cover on the driver side of the rear compartment.


Fuse Box Diagrams

2020

Engine Compartment Fuse Block
Cadillac CT4 (2020): Engine compartment fuse box diagram

List of fuses in the Engine Compartment Fuse Block (2020)

Usage
1Long range radar front sensor
2Park / Daytime running lamps
3Exterior lighting module 4
4Exterior lighting module 7
5Headlamp level
6
7Electronic brake control module
8Washer pump
9
10
11
12Horn
13Front wiper
14Exterior lighting module 6
15Exterior lighting module 1
16Exterior lighting module 5
17Exterior lighting module 3
18Aero shutter
19
20
21Virtual key system / Power sounder module
22
23Transmission control module
24Active engine mount
25
26Engine control module
27Injectors / Ignition 2
28Charged air cooler
29Transmission coolant pump
30Injectors / Ignition 1
31Emissions 1
32Emissions 2
33Starter solenoid
34
35Coolant pump
36Starter pinion
37AC clutch
38
39
40
41
42Water pump
43
44
Relays
47
48Front wiper speed
49Front wiper control
51
52Engine control module
53Starter solenoid
54Starter pinion
55
57AC clutch
58
Instrument Panel Fuse Block
Cadillac CT4 (2020): Instrument panel fuse box diagram

List of fuses in the Instrument Panel Fuse Block (2020)

Usage
1
2HVAC blower
3
4
5Theft deterrent / Universal garage door opener
6
7Air quality ionizer
8Heated steering wheel
9
10Electronic steering column lock 1
11
12
13
14
15
16
17
18Display / Infotainment/USB
19Airbag / Automatic occupant sensing / Data link connection / Wireless charging module
20Power steering column module / Electronic steering column lock 2
21
22
23
24
25USB
26
27
28
29
30
31Headlamp level
32
33Body ignition / IP ignition
34Exhaust valve
35Transmission control module ignition / Engine control module ignition / Shift ignition / Brake ignition
36Shift module
37Body control module 1 / Electronic park brake switch
38Center stack module
39Steering wheel controls
40Body control module 2
41Body control module 3
42Body control module 4
Circuit Breakers
CB1Auxiliary power outlet 1
CB2Auxiliary power outlet 2
Relays
1Run after park / Accessory
2Run crank
3
4
5
Rear Compartment Fuse Block
Cadillac CT4 (2020): Rear compartment fuse box diagram

List of fuses in the Rear Compartment Fuse Block (2020)

Usage
1Remote function actuator
2Engine control module
3Driver heated seat
4Fuel tank zone module
5
6
7
8
9
10Motor seat belt passenger
11Canister vent solenoid
12Sunroof
13
14
15Passenger heated seat
16
17Electronic suspension control
18
19Motor seat belt driver
20Rear defog
21DC to DC transformer 2
22Driver power window door lock switch
23External object calculating module / Front camera module
24Passenger window door lock switch
25
26Trailer
27Rear drive control module
28
29
30
31DC to DC transformer 1
32Transfer case electronic control
33Central gateway module / Side blind zone alert
34Video processing module
35Hands free closure release
36Exterior lighting module 2
37Passenger memory seat module
38Trailer 2
39Right front / Right rear window
40
41
42Amplifier
43Park assist module
44Driver memory seat module
45OnStar
46
47
48
49Trailer
50Driver seat
51Left front / Left rear window
52Passenger seat
Relays
53
54
55Run

2021

Engine Compartment Fuse Block
Cadillac CT4 (2021): Engine compartment fuse box diagram

List of fuses in the Engine Compartment Fuse Block (2021)

Usage
1Long range radar front sensor
2Park / Daytime running lamps
3Exterior lighting module 4
4Exterior lighting module 7
5Headlamp level
6
7Electronic brake control module
8Washer pump
9
10
11
12Horn
13Front wiper
14Exterior lighting module 6
15Exterior lighting module 1
16Exterior lighting module 5
17Exterior lighting module 3
18Aero shutter
19
20
21Virtual key system / Power sounder module
22Engine control module
23Transmission control module / Transmission reverse lock out
24Active engine mount
25
26Engine control module
27Injectors / Ignition 2
28Charged air cooler
29Transmission aux oil pump / Transmission reverse lock out
30Injectors / Ignition 1
31Emissions 1
32Emissions 2
33Starter solenoid
34
35
36Starter pinion
37AC clutch
38
39
40
41
42Water pump
43
44
Relays
47
48Front wiper speed
49Front wiper control
51
52Engine control module
53Starter solenoid
54Starter pinion
55
57AC clutch
58
Instrument Panel Fuse Block
Cadillac CT4 (2021): Instrument panel fuse box diagram

List of fuses in the Instrument Panel Fuse Block (2021)

Usage
1
2HVAC blower
3
4
5Theft deterrent / Universal garage door opener / Overhead console / Rain sensor
6
7Air quality ionizer
8Heated steering wheel
9
10Electronic steering column lock 1
11
12
13
14
15
16
17
18Display / Infotainment / USB / Multi-function control module
19Airbag / Automatic occupant sensing / Data link connection / Wireless charging module / Virtual key module
20Power steering column module / Electronic steering column lock 2
21Driver monitor system / Performance data recorder
22
23
24
25USB
26
27
28
29
30
31Headlamp level
32
33Body ignition / IP ignition
34Exhaust valve
35Transmission control module ignition / Engine control module ignition / Shift ignition / Brake ignition
36Shift module
37Body control module 1 / Electronic park brake switch
38Center stack module
39Steering wheel controls
40Body control module 2
41Body control module 3
42Body control module 4
Circuit Breakers
CB1Auxiliary power outlet 1
CB2Auxiliary power outlet 2
Relays
1Run after park / Accessory
2Run crank
3
4
5
Rear Compartment Fuse Block
Cadillac CT4 (2021): Rear compartment fuse box diagram

List of fuses in the Rear Compartment Fuse Block (2021)

Usage
1Remote function actuator
2
3Driver heated seat
4Fuel tank zone module
5
6
7
8
9
10Motor seat belt passenger
11Canister vent solenoid
12Sunroof
13
14
15Passenger heated seat
16
17Electronic suspension control
18
19Motor seat belt driver
20Rear defog
21DC to DC transformer 2
22Driver power window / Door handle switch
23External object calculating module / Front camera module / High definition localization / Short range radar
24Passenger power window / Door handle switch
25
26
27Rear drive control module
28
29
30
31DC to DC transformer 1
32Transfer case electronic control
33Central gateway module / Side blind zone alert
34Video processing module
35Hands free closure release
36Exterior lighting module 2
37Passenger memory seat module
38
39Right front / Right rear window
40
41
42Amplifier
43Park assist module
44Driver memory seat module
45OnStar
46
47
48
49
50Driver seat
51Left front / Left rear window
52Passenger seat
Relays
53
54
55Run

2022

Engine Compartment Fuse Block
Cadillac CT4 (2022): Engine compartment fuse box diagram

List of fuses in the Engine Compartment Fuse Block (2022)

Usage
1Long Range Radar Front Sensor
2Park/Daytime Running Lamps
3Exterior Lighting Module 4
4Exterior Lighting Module 7
5Headlamp Level
6
7Electronic Brake Control Module
8Washer Pump
9
10
11
12Horn
13Front Wiper
14Exterior Lighting Module 6
15Exterior Lighting Module 1
16Exterior Lighting Module 5
17Exterior Lighting Module 3
18Aero Shutter
19
20
21Virtual Key System / Power Sounder Module
22Engine Control Module Battery
23Transmission Control Module
24Active Engine Mount
25
26Engine Control Module
27Injectors / Ignition 2
28Charged Air Cooler
29Transmission Aux Oil Pump / Transmission Reverse Lock Out
30Injectors / Ignition 1
31Emissions 1
32Emissions 2
33Starter Solenoid
34
35
36Starter Pinion
37AC Clutch
38
39
40
41
42Water Pump
43
44
Relays
47
48Front Wiper Speed
49Front Wiper Control
51
52Engine Control Module
53Starter Solenoid
54Starter Pinion
55
57AC Clutch
58
Instrument Panel Fuse Block
Cadillac CT4 (2022): Instrument panel fuse box diagram

List of fuses in the Instrument Panel Fuse Block (2022)

Usage
1
2Heating, Ventilation, and Air Conditioning Blower
3
4
5Theft Deterrent / Universal Garage Door Opener / Overhead Console / Rain Sensor
6
7Air Quality Ionizer
8Heated Steering Wheel
9
10Electronic Steering Column Lock 1
11
12
13
14
15
16
17
18Display / Infotainment / USB / Multi-function Control Module
19Sensing and Diagnostic Module / Automatic Occupant Sensing / Data Link Connection / Wireless Charging Module / Virtual Key Module
20Power Steering Column Module / Electronic Steering Column Lock 2
21Driver Monitor System / Performance Data Recorder
22
23
24
25USB
26
27
28
29
30
31Headlamp Level
32
33Body Ignition / IP Ignition
34Exhaust Valve
35Transmission Control Module Ignition / Engine Control Module Ignition / Shift Ignition / Brake Ignition
36Shift Module
37Body Control Module 1 / Electronic Park Brake Switch
38Center Stack Module
39Steering Wheel Controls
40Body Control Module 2
41Body Control Module 3
42Body Control Module 4
Circuit Breakers
CB1Auxiliary Power Outlet 1
CB2Auxiliary Power Outlet 2
Relays
1Run After Park / Accessory
2Run Crank
3
4
5
Rear Compartment Fuse Block
Cadillac CT4 (2022): Rear compartment fuse box diagram

List of fuses in the Rear Compartment Fuse Block (2022)

Usage
1Remote Function Actuator
2
3Driver Heated Seat
4Fuel Tank Zone Module
5
6
7
8
9
10Motor Seat Belt Passenger
11Canister Vent Solenoid
12Sunroof
13
14
15Passenger Heated Seat
16
17Electronic Suspension Control
18
19Motor Seat Belt Driver
20Rear Defog
21DC to DC Transformer 2
22Driver Power Window / Door Handle Switch
23External Object Calculating Module / Front Camera Module / High Definition Localization Module / Short Range Radar
24Passenger Power Window / Door Handle Switch
25
26Amplifier (V-Series Blackwing)
27Rear Drive Control Module
28
29
30
31DC to DC Transformer 1
32Transfer Case Electronic Control
33Central Gateway Module / Side Blind Zone Alert
34Video Processing Module
35Hands Free Closure Release
36Exterior Lighting Module 2
37Passenger Memory Seat Module
38
39Right Front / Right Rear Window
40
41
42Amplifier
43Park Assist Module
44Driver Memory Seat Module
45OnStar
46
47
48
49
50Driver Seat
51Left Front / Left Rear Window
52Passenger Seat
Relays
53
54
55Run

2023

Engine Compartment Fuse Block
Cadillac CT4 (2023): Engine compartment fuse box diagram

List of fuses in the Engine Compartment Fuse Block (2023)

Usage
1Long Range Radar Front Sensor
2Park / Daytime Running Lamps
3Exterior Lighting Module 4
4Exterior Lighting Module 7
5Headlamp Level
6
7Electronic Brake Control Module
8Washer Pump
9
10
11
12Horn
13Front Wiper
14Exterior Lighting Module 6
15Exterior Lighting Module 1
16Exterior Lighting Module 5
17Exterior Lighting Module 3
18Aero Shutter
19
20
21Virtual Key System / Power Sounder Module
22Engine Control Module Battery
23Transmission Control Module
24Active Engine Mount
25
26Engine Control Module
27Injectors / lgnition 2
28Charged Air Cooler / Not Used
29Transmission Aux Oil Pump / Transmission Reverse Lock Out
30Injectors / lgnition 1
31Emissions 1
32Emissions 2
33Starter Solenoid
34
35
36Starter Pinion / Not Used
37AC Clutch
38
39
40
41
42Water Pump / Not Used
43
44
Relays
47
48Front Wiper Speed / Not Used
49Front Wiper Control
51
52Engine Control Module
53Starter Solenoid
54Starter Pinion / Not Used
55
57AC Clutch
58
Instrument Panel Fuse Block
Cadillac CT4 (2023): Instrument panel fuse box diagram

List of fuses in the Instrument Panel Fuse Block (2023)

Usage
1
2Heating, Ventilation, and Air Conditioning Blower
3
4
5Theft Deterrent / Universal Garage Door Opener / Overhead Console / Rain Sensor
6
7Air Quality Ionizer
8Heated Steering Wheel
9
10Electronic Steering Column Lock 1
11
12
13
14
15
16
17
18Display / lnfotainment / USB / Multi-function Control Module
19Sensing and Diagnostic Module / Automatic Occupant Sensing / Data Link Connection / Wireless Charging Module / Virtual Key Module
20Power Steering Column Module / Electronic Steering Column Lock 2
21Driver Monitor System / Performance Data Recorder
22
23
24
25USB
26
27
28
29
30
31Headlamp Level
32
33Body Ignition / IP Ignition
34Exhaust Valve
35Transmission Control Module Ignition / Engine Control Module Ignition / Shift Ignition / Brake Ignition
36Shift Module
37Body Control Module 1 / Electronic Park Brake Switch
38Center Stack Module
39Steering Wheel Controls
40Body Control Module 2
41Body Control Module 3
42Body Control Module 4
Circuit Breakers
CB1Auxiliary Power Outlet 1
CB2Auxiliary Power Outlet 2
Relays
1Run After Park / Accessory
2Run Crank
3
4
5
Rear Compartment Fuse Block
Cadillac CT4 (2023): Rear compartment fuse box diagram

List of fuses in the Rear Compartment Fuse Block (2023)

Usage
1Remote Function Actuator
2
3Driver Heated Seat
4Fuel Tank Zone Module
5
6
7
8
9
10Motor Seat Belt Passenger
11Canister Vent Solenoid
12Sunroof
13
14
15Passenger Heated Seat
16
17Electronic Suspension Control
18
19Motor Seat Belt Driver
20Rear Defog
21DC to DC Transformer 2
22Driver Power Window / Door Handle Switch
23External Object Calculating Module / Front Camera Module / High Definition Localization Module / Short Range Radar
24Passenger Power Window / Door Handle Switch
25
26Amplifier (V-Series Blackwing)
27Rear Drive Control Module
28
29
30
31DC to DC Transformer!
32Transfer Case Electronic Control
33Central Gateway Module / Side Blind Zone Alert
34Video Processing Module
35Hands Free Closure Release
36Exterior Lighting Module 2
37Passenger Memory Seat Module
38
39Right Front / Right Rear Window
40
41
42Amplifier
43Park Assist Module
44Driver Memory Seat Module
45OnStar
46
47
48
49
50Driver Seat
51Left Front / Left Rear Window
52Passenger Seat
Relays
53
54
55Run

2024

Engine Compartment Fuse Block
Cadillac CT4 (2024): Engine compartment fuse box diagram

List of fuses in the Engine Compartment Fuse Block (2024)

Usage
1Long Range Radar Front Sensor
2Park / Daytime Running Lamps
3Exterior Lighting Module 4
4Exterior Lighting Module 7
5Headlamp Level
6
7Electronic Brake Control Module
8Washer Pump
9
10
11
12Horn
13Front Wiper
14Exterior Lighting Module 6
15Exterior Lighting Module 1
16Exterior Lighting Module 5
17Exterior Lighting Module 3
18Aero Shutter
19
20
21Virtual Key System / Power Sounder Module
22Engine Control Module Battery
23Transmission Control Module
24Active Engine Mount
25
26Engine Control Module
27Injectors / lgnition 2
28Charged Air Cooler / Not Used
29Transmission Aux Oil Pump / Transmission Reverse Lock Out
30Injectors / lgnition 1
31Emissions 1
32Emissions 2
33Starter Solenoid
34
35
36Starter Pinion / Not Used
37AC Clutch
38
39
40
41
42Water Pump / Not Used
43
44
Relays
47
48Front Wiper Speed / Not Used
49Front Wiper Control
51
52Engine Control Module
53Starter Solenoid
54Starter Pinion / Not Used
55
57AC Clutch
58
Instrument Panel Fuse Block
Cadillac CT4 (2024): Instrument panel fuse box diagram

List of fuses in the Instrument Panel Fuse Block (2024)

Usage
1
2Heating, Ventilation, and Air Conditioning Blower
3
4
5Theft Deterrent / Universal Garage Door Opener / Overhead Console / Rain Sensor
6
7Air Quality Ionizer
8Heated Steering Wheel
9
10Electronic Steering Column Lock 1
11
12
13
14
15
16
17
18Display / lnfotainment / USB / Multi-function Control Module
19Sensing and Diagnostic Module / Automatic Occupant Sensing / Data Link Connection / Wireless Charging Module / Virtual Key Module
20Power Steering Column Module / Electronic Steering Column Lock 2
21Driver Monitor System / Performance Data Recorder
22
23
24
25USB
26
27
28
29
30
31Headlamp Level / Spare
32
33Body Ignition / IP Ignition
34Exhaust Valve
35Transmission Control Module Ignition / Engine Control Module Ignition / Shift Ignition / Brake Ignition
36Shift Module
37Body Control Module 1 / Electronic Park Brake Switch
38Center Stack Module
39Steering Wheel Controls
40Body Control Module 2
41Body Control Module 3
42Body Control Module 4
Circuit Breakers
CB1Auxiliary Power Outlet 1
CB2Auxiliary Power Outlet 2
Relays
1Run After Park / Accessory
2Run Crank
3
4
5
Rear Compartment Fuse Block
Cadillac CT4 (2024): Rear compartment fuse box diagram

List of fuses in the Rear Compartment Fuse Block (2024)

Usage
1Remote Function Actuator
2
3Driver Heated Seat
4Fuel Tank Zone Module
5
6
7
8
9
10Motor Seat Belt Passenger
11Canister Vent Solenoid
12Sunroof
13
14
15Passenger Heated Seat
16
17Electronic Suspension Control
18
19Motor Seat Belt Driver
20Rear Defog
21DC to DC Transformer 2
22Driver Power Window / Door Handle Switch
23External Object Calculating Module / Front Camera Module / High Definition Localization Module / Short Range Radar
24Passenger Power Window / Door Handle Switch
25
26Amplifier (V-Series Blackwing)
27Rear Drive Control Module
28
29
30
31DC to DC Transformer 1
32Transfer Case Electronic Control
33Central Gateway Module / Side Blind Zone Alert
34Video Processing Module
35Hands Free Closure Release
36Exterior Lighting Module 2
37Passenger Memory Seat Module
38
39Right Front / Right Rear Window
40
41
42Amplifier
43Park Assist Module
44Driver Memory Seat Module
45OnStar
46
47
48
49
50Driver Seat
51Left Front / Left Rear Window
52Passenger Seat
Relays
53
54
55Run

Conclusion

The 2020-2024 Cadillac CT4 offers luxury and performance in a compact form, supported by a well-structured electrical system. Maintaining the fuse boxes and relays is vital for dependable functionality.

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