Access Cadillac CT4 fuse box diagrams for 2020–2026 models with relay locations, fuse assignments, panel layouts, and detailed electrical system information. This article covers the compact executive sedan Cadillac CT4 , available from 2020 , and includes fuse box diagrams for Cadillac CT4 2020, 2021, 2022, 2023, 2024, 2025 and 2026 , along with details about the location of the fuse panels inside the vehicle and a clear explanation of the assignment of each fuse and relay (fuse layout).
The engine compartment fuse block is located on the driver’s side of the engine compartment. Raise the cover to reach the fuses.
Assignment of the fuses in the engine compartment
Fuse Data
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No. Description 1 Long range radar front sensor 2 2020-2025: Park/Daytime running lamps3 Exterior lighting module 4 4 Exterior lighting module 7 5 Headlamp level 6 Not Used 7 Electronic brake control module 8 Washer pump 9 Not Used 10 Not Used 11 Not Used 12 Horn 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 Not Used 20 Not Used 21 2020-2025: Virtual key system/ Power sounder module2026: Automatic Light Module/ Power Sounder Module22 Engine control module 23 Transmission control module/Transmission reverse lock out 24 Active engine mount 25 Not Used 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 Not Used 35 Not Used 36 Starter pinion 37 2020-2025: AC clutch38 Not Used 39 Not Used 40 Not Used 41 Not Used 42 Water pump 43 Not Used 44 Not Used
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Assignment of the relays in the engine compartment
Fuse Data
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No. Description 47 Not Used 48 Front wiper speed 49 Front wiper control 51 Not Used 52 Engine control module 53 Starter solenoid 54 Starter pinion 55 Not Used 57 AC clutch 58 Not Used
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The instrument panel fuse block is located at the outer end of the driver side of the instrument panel. To reach it, remove the end cover by carefully prying near each clip with a plastic tool, starting at the point shown.
To install the cover, place the tabs on the back of the cover into the slots in the instrument panel. Line up the clips with the slots in the instrument panel, then press the cover into position.
Assignment of the fuses in the passenger compartment
Fuse Data
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No. Description 1 Not Used 2 Heating, Ventilation, and Air Conditioning Blower 3 Not Used 4 Not Used 5 2020-2021: Theft deterrent/ Universal garage door opener2022-2026: Rain/Theft Deterrent/ Over Head Console/ Universal Garage Door Opener6 Not Used 7 2020-2025: Air quality ionizer8 Heated steering wheel 9 Not Used 10 Electronic steering column lock 1 11 Not Used 12 Not Used 13 Not Used 14 Not Used 15 Not Used 16 Not Used 17 Not Used 18 Display/ Infotainment/ USB/ CSM 19 2020-2021: Airbag/Automatic occupant sensing/ Data link connection/ Wireless charging module2022-2026: Sensing and Diagnostic Module/ Automatic Occupant Sensing/ Data Link Connection/ Wireless Charging Module/ Virtual Key Module20 Power steering column module/ Electronic steering column lock 2 21 2021-2026: Driver monitor system/ Performance data recorder22 Not Used 23 Not Used 24 Not Used 25 USB 26 Not Used 27 Not Used 28 Not Used 29 Not Used 30 Not Used 31 Headlamp level 32 Not Used 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 39 Steering wheel controls 40 Body control module 2 41 Body control module 3 42 Body control module 4
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Assignment of the circuit breakers in the passenger compartment
Fuse Data
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CB1 Auxiliary power outlet 1 CB2 Auxiliary power outlet 2
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Assignment of the relays in the passenger compartment
Fuse Data
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No. Description 1 Run after park/ Accessory 2 Run crank 3 Not Used 4 Not Used 5 Not Used
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The rear compartment fuse block is located behind a cover on the driver side of the rear compartment.
Assignment of the fuses in the rear compartment
Fuse Data
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No. Description 1 Remote function actuator 2 Not Used 3 Driver heated seat 4 Fuel tank zone module 5 Not Used 6 Not Used 7 Not Used 8 Not Used 9 Not Used 10 Motor seat belt passenger 11 Canister vent solenoid 12 Sunroof 13 Not Used 14 Not Used 15 Passenger heated seat 16 Not Used 17 Electronic suspension control 18 Not Used 19 Motor seat belt driver 20 Rear defog 21 DC to DC transformer 2 22 Driver power window door lock switch 23 External object calculating module/ Front camera module/High definition localization/Short range radar 24 Passenger window door lock switch 25 Not Used 26 Amplifier (V-series) 27 Rear drive control module 28 Not Used 29 Not Used 30 Not Used 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 Not Used 39 Right front/ Right rear window 40 Not Used 41 Not Used 42 Amplifier 43 Park assist module 44 Driver memory seat module 45 OnStar 46 Not Used 47 Not Used 48 Not Used 49 Not Used 50 Driver seat 51 Left front/Left rear window 52 Passenger seat
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Assignment of the relays in the rear compartment
Fuse Data
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No. Description 53 Not Used 54 Not Used 55 Run
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