2021 Cadillac CT4 Electrical Switch & Relay Parts: OEM & Replacement (55 Parts)

The 2021 Cadillac CT4 has 55 electrical switch & relay parts with verified fitment on this page — 28 part types and 10 brands, covering both the 2.0L L4 Turbocharged and the 2.7L L4 Turbocharged. Each part includes a manufacturer part number and application notes.

On the 2021 Cadillac CT4, the switch and relay system covers the switches, relays and flashers that route power to everything the driver touches. Most of the listed parts are Oil Pressure Sender / Switch (6 parts), Hazard Warning Switch (5 parts) and Overdrive Switch (5 parts). The other 25 part types cover the remaining 39 parts.

A/C Compressor Relay

Brand	Part Number	Markets	Notes	Buy
GM GENUINE Fits: 2.7L L4 Turbocharged	13500113	🇺🇸 US 🇨🇦 CA	Black Fitment notes — GM GENUINE 13500113 Black 20AMP4-TerminalMultiuseControl Relay	View on Amazon

This table covers the relays that control the A/C Compressor circuit. Typical signs include a click with no action, or a circuit that works only when you swap in a known-good relay. Swap with an identical relay in the fuse box before buying — it is the fastest test there is.

A/C Refrigerant Pressure Switch

Brand	Part Number	Markets	Notes	Buy
GM GENUINE Fits: 2.7L L4 Turbocharged	1551388	🇺🇸 US 🇨🇦 CA	Mating Connector Use 86792094with Integrated Circuit	View on Amazon
UAC Fits: 2.7L L4 Turbocharged	SW11475C	🇺🇸 US 🇨🇦 CA	High Pressure Switch	View on Amazon

This table covers the pressure switches on the A/C circuit. Typical signs include a function that works intermittently, or a click without the accessory coming on. Inspect the connector behind the switch; heat-damaged terminals will kill the new part too.

A/C System Relay

Brand	Part Number	Markets	Notes	Buy
UAC Fits: 2.7L L4 Turbocharged	RE0959C	🇺🇸 US 🇨🇦 CA		View on Amazon

This table covers the relays that control the A/C System circuit. Typical signs include a click with no action, or a circuit that works only when you swap in a known-good relay. Swap with an identical relay in the fuse box before buying — it is the fastest test there is.

Accessory Power Relay

Brand	Part Number	Markets	Notes	Buy
HELLA Fits: 2.7L L4 Turbocharged	933332571	🇺🇸 US 🇨🇦 CA	30 Amps4-Pin Connector Fitment notes — HELLA 933332571 30 Amps4-Pin ConnectorColor: Black or Gray	View on Amazon

This table covers the relays that control the Accessory Power circuit. Typical signs include a click with no action, or a circuit that works only when you swap in a known-good relay. Swap with an identical relay in the fuse box before buying — it is the fastest test there is.

Blower Motor Relay

Brand	Part Number	Markets	Notes	Buy
HELLA Fits: 2.7L L4 Turbocharged	933332571	🇺🇸 US 🇨🇦 CA	30 Amps4-Pin Connector Fitment notes — HELLA 933332571 30 Amps4-Pin ConnectorColor: Black or Gray	View on Amazon

This table covers the relays that control the Blower Motor circuit. Typical signs include a click with no action, or a circuit that works only when you swap in a known-good relay. Swap with an identical relay in the fuse box before buying — it is the fastest test there is.

Brake Light Switch

Brand	Part Number	Markets	Notes	Buy
VEMO Fits: 2.7L L4 Turbocharged	V51730196	🇺🇸 US 🇨🇦 CA	Stop Light Switch, 3 Pins	View on Amazon

This table covers the pedal-mounted switch that turns on the brake lamps. Typical signs include a function that works intermittently, or a click without the accessory coming on. Inspect the connector behind the switch; heat-damaged terminals will kill the new part too.

Cruise Control Switch

Brand	Part Number	Markets	Notes	Buy
GM GENUINE Fits: 2.7L L4 Turbocharged	13536138	🇺🇸 US 🇨🇦 CA	Fits Premium LuxuryAutomatic Transmission Manual Shift Control (KBC), Steering Wheel with Automatic Heat (KI3), Leather Wrapped Steering Wheel (NP5), Forward Collision Alert (UEU) Fitment notes — GM GENUINE 13536138 Fits: Premium LuxuryAutomatic Transmission Manual Shift Control (KBC), Steering Wheel with Automatic Heat (KI3), Leather Wrapped Steering Wheel (NP5), Forward Collision Alert (UEU) or: Premium LuxuryManual Shift Automatic Transmission (KB7), Steering Wheel with Automatic Heat (KI3), Leather Wrapped Sport Steering Wheel (NK4), Forward Collision Alert (UEU)Exc. Steering Wheel Color (53S) or: V ModelManual Shift Automatic Transmission (KB7), Steering Wheel with Automatic Heat (KI3), Leather Wrapped Sport Steering Wheel (NK4), Forward Collision Alert (UEU)Exc. PTM Knob Steering Wheel Identification(BTH), Steering Wheel Color (53S)	View on Amazon
GM GENUINE Fits: 2.7L L4 Turbocharged	13543447	🇺🇸 US 🇨🇦 CA	Fits LeftPremium Luxury Fitment notes — GM GENUINE 13543447 Fits: LeftPremium LuxuryManual Shift Automatic Trans. (KB7),Auto Heat Steering Wheel(KI3), Leather Wrapped Sport Steering Wheel(NK4),Forward Collision Alert (UEU)Jet BlackExc. Steering Wheel Color (53S)Cruise with FCA and HeatLabeled 13543447 or: LeftV ModelManual Shift Automatic Trans. (KB7),Auto Heat Steering Wheel(KI3), Leather Wrapped Sport Steering Wheel(NK4),Forward Collision Alert (UEU)Jet BlackExcept PTM Knob Steering Wheel Identification (BTH), Steering Wheel Color (53S)Cruise with FCA and HeatLabeled 13543447	View on Amazon
GM GENUINE Fits: 2.7L L4 Turbocharged	13551229	🇺🇸 US 🇨🇦 CA	Fits LeftPremium Luxury Fitment notes — GM GENUINE 13551229 Fits: LeftPremium LuxuryLabeled 13551229,13536137,84186052Jet BlackExc. Auto Heat Steering Wheel(KI3)Automatic Transmission Manual Shift Control (KBC), Leather Wrapped Steering Wheel (NP5), Forward Collision Alert (UEU) or: LeftV ModelManual Shift Automatic Transmission (KB7), Leather Wrapped Sport Steering Wheel (NK4), Forward Collision Alert (UEU)Labeled 13551229,13536137,84186052Jet BlackExc. Auto Heat Steering Wheel(KI3)	View on Amazon
GM GENUINE Fits: 2.7L L4 Turbocharged	13551231	🇺🇸 US 🇨🇦 CA	Fits LeftManual Shift Automatic Trans. (KB7),AUTO HEAT STEERING WHEEL(KI3), LEATHER WRAPPED SPORT Steering Wheel(NK4),Forward Collision Alert (UEU) Fitment notes — GM GENUINE 13551231 Fits: LeftManual Shift Automatic Trans. (KB7),AUTO HEAT STEERING WHEEL(KI3), LEATHER WRAPPED SPORT Steering Wheel(NK4),Forward Collision Alert (UEU)LABELED 13551231JET BLACKExc. Steering Wheel Color (53S) or: LeftPremium LuxuryLABELED 13551231JET BLACKAutomatic Transmission Manual Shift Control (KBC),AUTO HEAT STEERING WHEEL(KI3), Leather Wrapped Steering Wheel (NP5),Forward Collision Alert (UEU) or: LeftV ModelManual Shift Automatic Trans. (KB7),Auto Heat Steering Wheel(KI3), Leather Wrapped Sport Steering Wheel(NK4),Forward Collision Alert (UEU)Labeled 13551231Jet BlackExcept PTM Knob Steering Wheel Identification (BTH), Steering Wheel Color (53S)	View on Amazon

This table covers the Cruise Control switches. Typical signs include a function that works intermittently, or a click without the accessory coming on. Inspect the connector behind the switch; heat-damaged terminals will kill the new part too.

Dimmer Switch

Brand	Part Number	Markets	Notes	Buy
GM GENUINE Fits: 2.7L L4 Turbocharged	84534437	🇺🇸 US 🇨🇦 CA	JET BLACK	View on Amazon
WELLS Fits: 2.7L L4 Turbocharged	1S17947	🇺🇸 US 🇨🇦 CA		View on Amazon

This table covers the dimmer switches that select headlamp high and low beam. Typical signs include a function that works intermittently, or a click without the accessory coming on. Inspect the connector behind the switch; heat-damaged terminals will kill the new part too.

Door Lock Relay

Brand	Part Number	Markets	Notes	Buy
GM GENUINE Fits: 2.7L L4 Turbocharged	D1780C	🇺🇸 US 🇨🇦 CA	Black Fitment notes — GM GENUINE D1780C Black Rear35AMP5 TERMINALHIGH CURRENT MICRO 280	View on Amazon

This table covers the relays that control the Door Lock circuit. Typical signs include a click with no action, or a circuit that works only when you swap in a known-good relay. Swap with an identical relay in the fuse box before buying — it is the fastest test there is.

Driver Information Display Switch

Brand	Part Number	Markets	Notes	Buy
GM GENUINE Fits: 2.7L L4 Turbocharged	85654932	🇺🇸 US 🇨🇦 CA	Programming Required: YES Fitment notes — GM GENUINE 85654932 Programming Required: YES Labeled 85654932, 85593153, 84891121, 84891119, 84722806, 84722804Jet BlackElectronic Transmission Range Select (EPH), 3.0 Mid/High HMI, Enhanced Radio Infotainment System with Premium Navigation (IOT)	View on Amazon

This table covers the Driver Information Display switches. Typical signs include a function that works intermittently, or a click without the accessory coming on. Inspect the connector behind the switch; heat-damaged terminals will kill the new part too.

Engine Control Module Relay

Brand	Part Number	Markets	Notes	Buy
GM GENUINE Fits: 2.7L L4 Turbocharged	13422668	🇺🇸 US 🇨🇦 CA	Gray4-Terminal	View on Amazon

This table covers the relays that control the Engine Control Module circuit. Typical signs include a click with no action, or a circuit that works only when you swap in a known-good relay. Swap with an identical relay in the fuse box before buying — it is the fastest test there is.

Fuel Pump / Circuit Opening Relay

Brand	Part Number	Markets	Notes	Buy
HELLA Fits: 2.7L L4 Turbocharged	933332571	🇺🇸 US 🇨🇦 CA	30 Amps4-Pin Connector Fitment notes — HELLA 933332571 30 Amps4-Pin ConnectorColor: Black or Gray	View on Amazon

This table covers the relays that control the Fuel Pump / Circuit Opening circuit. Typical signs include a click with no action, or a circuit that works only when you swap in a known-good relay. Swap with an identical relay in the fuse box before buying — it is the fastest test there is.

Hazard Warning Switch

Brand	Part Number	Markets	Notes	Buy
GM GENUINE Fits: 2.7L L4 Turbocharged	84544724	🇺🇸 US 🇨🇦 CA	Black Fitment notes — GM GENUINE 84544724 Black Fits: Park Assist with Indicator Sensor (UD5), Rear Parking Assist/Obstacle Detection Sensor (UD7)Except Seat Heater (KA1), Driver and Passenger Ventilated Front Seats(KU9), Lane Keep Assist Sensor Indicator (UHX), Lane Active Safety Keep Assist(UKL) or: Seat Heater (KA1),Driver and Passenger Ventilated Front Seats(KU9),Park Assist with Indicator Sensor (UD5),Rear Parking Assist/Obstacle Detection Sensor (UD7),without Front Heat / Vent Seats (00V)Except Lane Keep Assist Sensor Indicator (UHX), Lane Active Safety Keep Assist(UKL) or: Seat Heater (KA1),Park Assist with Indicator Sensor (UD5),Rear Parking Assist/Obstacle Detection Sensor (UD7),without Front Heat / Vent Seats (00V)Except Driver and Passenger Ventilated Front Seats(KU9), Lane Keep Assist Sensor Indicator (UHX), Lane Active Safety Keep Assist(UKL)	View on Amazon
GM GENUINE Fits: 2.7L L4 Turbocharged	84544726	🇺🇸 US 🇨🇦 CA	Black Fitment notes — GM GENUINE 84544726 Black Fits: Seat Heater (KA1),Park Assist with Indicator Sensor (UD5),Rear Parking Assist/Obstacle Detection Sensor (UD7), Lane Keep Assist Sensor Indicator (UHX), Lane Active Safety Keep Assist(UKL),Mono HD Digital Vision with 360 View (UV2),without Front Heat / Vent SeatsExc. Driver and Passenger Ventilated Front Seats(KU9) or: Seat Heater (KA1),Park Assist with Indicator Sensor (UD5),Rear Parking Assist/Obstacle Detection Sensor (UD7), Lane Keep Assist Sensor Indicator (UHX), Lane Active Safety Keep Assist(UKL),without Front Heat / Vent Seats (00V)Except Driver and Passenger Ventilated Front Seats (KU9), Mono HD Digital Vision with 360 View (UV2)	View on Amazon
GM GENUINE Fits: 2.7L L4 Turbocharged	84544736	🇺🇸 US 🇨🇦 CA	Black Fitment notes — GM GENUINE 84544736 Black Seat Heater (KA1), Driver and Passenger Ventilated Front Seats (KU9), Park Assist with Indicator Sensor (UD5), Rear Parking Assist/Obstacle Detection Sensor (UD7), Lane Keep Assist Sensor Indicator (UHX), Lane Active Safety Keep Assist (UKL)Except Mono HD Digital Vision with 360 View (UV2)	View on Amazon
GM GENUINE Fits: 2.7L L4 Turbocharged	84544738	🇺🇸 US 🇨🇦 CA	Black Fitment notes — GM GENUINE 84544738 Black Seat Heater (KA1), Park Assist with Indicator Sensor (UD5), Rear Parking Assist/Obstacle Detection Sensor (UD7), Lane Keep Assist Sensor Indicator (UHX), Lane Active Safety Keep Assist (UKL)Except Driver and Passenger Ventilated Front Seats (KU9), Mono HD Digital Vision with 360 View (UV2)	View on Amazon
GM GENUINE Fits: 2.7L L4 Turbocharged	84544744	🇺🇸 US 🇨🇦 CA	Black Fitment notes — GM GENUINE 84544744 Black Seat Heater (KA1), Driver and Passenger Ventilated Front Seats (KU9), Park Assist with Indicator Sensor (UD5), Rear Parking Assist/Obstacle Detection Sensor (UD7)Except Lane Keep Assist Sensor Indicator (UHX), Lane Active Safety Keep Assist (UKL), without Front Heat / Vent Seats (00V)	View on Amazon

This table covers the Hazard Warning switches. Typical signs include a function that works intermittently, or a click without the accessory coming on. Inspect the connector behind the switch; heat-damaged terminals will kill the new part too.

Horn Relay

Brand	Part Number	Markets	Notes	Buy
HELLA Fits: 2.7L L4 Turbocharged	933332571	🇺🇸 US 🇨🇦 CA	30 Amps4-Pin Connector Fitment notes — HELLA 933332571 30 Amps4-Pin ConnectorColor: Black or Gray	View on Amazon

This table covers the relays that control the Horn circuit. Typical signs include a click with no action, or a circuit that works only when you swap in a known-good relay. Swap with an identical relay in the fuse box before buying — it is the fastest test there is.

Ignition Relay

Brand	Part Number	Markets	Notes	Buy
GM GENUINE Fits: 2.7L L4 Turbocharged	D1780C	🇺🇸 US 🇨🇦 CA	Black Fitment notes — GM GENUINE D1780C Black BLACK35AMP5 TERMINALHIGH CURRENT MICRO 280	View on Amazon

This table covers the relays that control the Ignition circuit. Typical signs include a click with no action, or a circuit that works only when you swap in a known-good relay. Swap with an identical relay in the fuse box before buying — it is the fastest test there is.

Ignition Starter Switch

Brand	Part Number	Markets	Notes	Buy
WELLS Fits: 2.7L L4 Turbocharged	1S17923	🇺🇸 US 🇨🇦 CA		View on Amazon

This table covers the ignition switches that feed the starter circuit. Typical signs include a function that works intermittently, or a click without the accessory coming on. Inspect the connector behind the switch; heat-damaged terminals will kill the new part too.

Multi-Function Relay

Brand	Part Number	Markets	Notes	Buy
WELLS Fits: 2.7L L4 Turbocharged	1R2208	🇺🇸 US 🇨🇦 CA	Mounting Hardware Included: No Fitment notes — WELLS 1R2208 Mounting Hardware Included: No with 4 Terminals	View on Amazon

This table covers the relays that control the Multi-Function circuit. Typical signs include a click with no action, or a circuit that works only when you swap in a known-good relay. Swap with an identical relay in the fuse box before buying — it is the fastest test there is.

Oil Pressure Sender / Switch

Economy

Brand	Part Number	Markets	Notes	Buy
DORMAN Fits: 2.7L L4 Turbocharged	926397	🇺🇸 US 🇨🇦 CA	3 Way with Leadswith Flat Connector	View on Amazon
HOLSTEIN Fits: 2.7L L4 Turbocharged	2OPS0020	🇺🇸 US 🇨🇦 CA	with Light	View on Amazon
UNITED MOTOR PRODUCTS Fits: 2.7L L4 Turbocharged	OPS322	🇺🇸 US 🇨🇦 CA	with Light	View on Amazon
WALKER PRODUCTS Fits: 2.7L L4 Turbocharged	2561004	🇺🇸 US 🇨🇦 CA	Includes Seal	View on Amazon

Standard Replacement

Brand	Part Number	Markets	Notes	Buy
STANDARD MOTOR PRODUCTS Popular Fits: 2.7L L4 Turbocharged	PS623	🇺🇸 US 🇨🇦 CA	Connector Shape: Rectangle, OvalSensor Only	View on Amazon
WELLS Popular Fits: 2.7L L4 Turbocharged	1S12693	🇺🇸 US 🇨🇦 CA	Connector Gender: Female	View on Amazon

This table covers the senders and switches that report oil pressure to the gauge or lamp. Typical signs include a lamp that stays on, or a gauge that never moves. Confirm power and ground at the connector before replacing the sender or switch.

Overdrive Switch

Brand	Part Number	Markets	Notes	Buy
GM GENUINE Popular Fits: 2.7L L4 Turbocharged	13532993	🇺🇸 US 🇨🇦 CA	Fits LeftPremium Luxury Fitment notes — GM GENUINE 13532993 Fits: LeftPremium LuxuryLabeled 13532993Jet BlackAutomatic Transmission Manual Shift Control (KBC), Steering Wheel with Automatic Heat (KI3), Leather Wrapped Steering Wheel (NP5), Forward Collision Alert (UEU)Steering Wheel Transmission Shift Control Switch or: LeftPremium LuxuryLabeled 13532993Jet BlackExc. Steering Wheel with Automatic Heat (KI3)Automatic Transmission Manual Shift Control (KBC), Leather Wrapped Steering Wheel (NP5), Forward Collision Alert (UEU)Steering Wheel Transmission Shift Control Switch	View on Amazon
GM GENUINE Fits: 2.7L L4 Turbocharged	13535952	🇺🇸 US 🇨🇦 CA	Fits LeftPremium Luxury Fitment notes — GM GENUINE 13535952 Fits: LeftPremium LuxuryShift Control Manual Shift, Automatic Transmission, VAR 1, Leather Wrapped Steering Wheel (NP5),Forward Collision Alert (UEU)Labeled 13535952Jet BlackExc. Auto Heat Steering Wheel(KI3)Steering Wheel Transmission Shift Control Switch or: LeftPremium LuxuryShift Control Manual Shift, Automatic Transmission, VAR 1,Auto Heat Steering Wheel(KI3), Leather Wrapped Steering Wheel (NP5),Forward Collision Alert (UEU)Labeled 13535952Jet BlackSteering Wheel Transmission Shift Control Switch	View on Amazon
GM GENUINE Fits: 2.7L L4 Turbocharged	13535954	🇺🇸 US 🇨🇦 CA	Fits RightPremium Luxury Fitment notes — GM GENUINE 13535954 Fits: RightPremium LuxuryLabeled 13535954, 13532995, 84186060Jet BlackAutomatic Transmission Manual Shift Control (KBC), Auto Heat Steering Wheel (KI3), Leather Wrapped Steering Wheel (NP5), Forward Collision Alert (UEU)Steering Wheel Transmission Shift Control Switch or: RightPremium LuxuryLabeled 13535954, 13532995, 84186060Jet BlackExc. Auto Heat Steering Wheel(KI3)Automatic Transmission Manual Shift Control (KBC), Leather Wrapped Steering Wheel (NP5), Forward Collision Alert (UEU)Steering Wheel Transmission Shift Control Switch or: RightPremium LuxuryLabeled 13535954, 13532995, 84186060Jet BlackAutomatic Transmission Manual Shift Control (KBC), Leather Wrapped Steering Wheel (NP5), Forward Collision Alert (UEU)Steering Wheel Transmission Shift Control Switch	View on Amazon
GM GENUINE Fits: 2.7L L4 Turbocharged	13545791	🇺🇸 US 🇨🇦 CA	Fits LeftPremium Luxury Fitment notes — GM GENUINE 13545791 Fits: LeftPremium LuxuryManual Shift Automatic Transmission (KB7), Auto Heat Steering Wheel (KI3), Leather Wrapped Sport Steering Wheel (NK4), Forward Collision Alert (UEU)Labeled 13545791,13535951,13532992,13522524,84186063Galvano SilverExc. Steering Wheel Color (53S)Steering Wheel Transmission Shift Control Switch or: LeftPremium LuxuryManual Shift Automatic Transmission (KB7), Auto Heat Steering Wheel (KI3), Deluxe Steering Wheel (N30), Forward Collision Alert (UEU)Labeled 13545791,13535951,13532992,13522524,84186063Galvano SilverExc. PTM Knob Steering Wheel Identification(BTH),Steering Wheel Color (53S)Steering Wheel Transmission Shift Control Switch or: LeftLabeled 13545791,13535951,13532992,13522524,84186063Galvano SilverAuto Heat Steering Wheel (KI3), Deluxe Steering Wheel (N30), Forward Collision Alert (UEU)Steering Wheel Transmission Shift Control Switch or: LeftLabeled 13545791,13535951,13532992,13522524,84186063Galvano SilverAuto Heat Steering	View on Amazon
GM GENUINE Fits: 2.7L L4 Turbocharged	13545793	🇺🇸 US 🇨🇦 CA	Fits RightV Model Fitment notes — GM GENUINE 13545793 Fits: RightV ModelManual Shift Automatic Transmission (KB7), Auto Heat Steering Wheel (KI3), Leather Wrapped Sport Steering Wheel (NK4), Forward Collision Alert (UEU)Labeled 13545793Galvano SilverSteering Wheel Transmission Shift Control Switch or: RightV ModelManual Shift Automatic Transmission (KB7), Leather Wrapped Sport Steering Wheel (NK4), Forward Collision Alert (UEU)Labeled 13545793Galvano SilverExc. Auto Heat Steering Wheel(KI3)Steering Wheel Transmission Shift Control Switch or: RightPremium LuxuryManual Shift Automatic Transmission (KB7), Leather Wrapped Sport Steering Wheel (NK4), Forward Collision Alert (UEU)Labeled 13545793Galvano SilverExc. Steering Wheel Color (53S)Steering Wheel Transmission Shift Control Switch or: RightLabeled 13545793Galvano SilverAuto Heat Steering Wheel (KI3), Deluxe Steering Wheel (N30), Forward Collision Alert (UEU)Steering Wheel Transmission Shift Control Switch or: RightLabeled 13545793Galvano SilverAuto	View on Amazon

This table covers the Overdrive switches. Typical signs include a function that works intermittently, or a click without the accessory coming on. Inspect the connector behind the switch; heat-damaged terminals will kill the new part too.

Power Window Switch

Brand	Part Number	Markets	Notes	Buy
GM GENUINE Fits: 2.7L L4 Turbocharged	84567042	🇺🇸 US 🇨🇦 CA	Fits RearPremium Luxury Fitment notes — GM GENUINE 84567042 Fits: RearPremium LuxuryLeather Interior Trim Color (H1Y), Deluxe Interior Lamp Package (TSQ), Premium Speaker System with Surround Amplifier (UQS), Interior Trim Color (4AA)Labeled 84567042Jet BlackChrome Tips or: RearPremium LuxuryLeather Interior Trim Configuration (H0M), Deluxe Interior Lamp Package (TSQ), Premium Speaker System with Surround Amplifier (UQS), Interior Trim Color (4FV)Labeled 84567042Jet BlackChrome Tips or: RearPremium LuxuryLeather Interior Trim Configuration (HNC), Deluxe Interior Lamp Package (TSQ), Premium Speaker System with Surround Amplifier (UQS), Interior Trim Color (4JO)Labeled 84567042Jet BlackChrome Tips or: RearV ModelLeather Interior Trim Configuration (H0L), Deluxe Interior Lamp Package (TSQ), Premium Speaker System with Surround Amplifier (UQS), Interior Trim Color (4EP)Labeled 84567042Jet BlackChrome Tips or: RearPremium LuxuryLeather Interior Trim Configuration (HUN), Deluxe Interior Lamp Package (TSQ), Premium Speaker S	View on Amazon
STANDARD MOTOR PRODUCTS Fits: 2.7L L4 Turbocharged	DWS2274	🇺🇸 US 🇨🇦 CA	Front Rightwith Type 1	View on Amazon
STANDARD MOTOR PRODUCTS Fits: 2.7L L4 Turbocharged	DWS2296	🇺🇸 US 🇨🇦 CA	Rear	View on Amazon

This table covers the switches that command each window motor. Typical signs include a function that works intermittently, or a click without the accessory coming on. Inspect the connector behind the switch; heat-damaged terminals will kill the new part too.

Pulse Wiper Relay

Brand	Part Number	Markets	Notes	Buy
GM GENUINE Fits: 2.7L L4 Turbocharged	D1780C	🇺🇸 US 🇨🇦 CA	Black Fitment notes — GM GENUINE D1780C Black BLACK35AMP5 TERMINALHIGH CURRENT MICRO 280	View on Amazon

This table covers the relays that control the Pulse Wiper circuit. Typical signs include a click with no action, or a circuit that works only when you swap in a known-good relay. Swap with an identical relay in the fuse box before buying — it is the fastest test there is.

Radiator Fan Relay

Brand	Part Number	Markets	Notes	Buy
STANDARD MOTOR PRODUCTS Fits: 2.7L L4 Turbocharged	RY232	🇺🇸 US 🇨🇦 CA	Amperage Rating: 35 AConnector Gender: Male Fitment notes — STANDARD MOTOR PRODUCTS RY232 Amperage Rating: 35 AConnector Gender: MaleFunctions: Multi-Function Relayblack Motor Relay	View on Amazon

This table covers the relays that control the Radiator Fan circuit. Typical signs include a click with no action, or a circuit that works only when you swap in a known-good relay. Swap with an identical relay in the fuse box before buying — it is the fastest test there is.

Starter Motor Control Relay

Brand	Part Number	Markets	Notes	Buy
GM GENUINE Fits: 2.7L L4 Turbocharged	13455281	🇺🇸 US 🇨🇦 CA	Black Fitment notes — GM GENUINE 13455281 Black 35AMP4-Terminal, Songhuan4-Terminal, 35 Amp, Black, SonghuanAccessory	View on Amazon
GM GENUINE Fits: 2.7L L4 Turbocharged	13500114	🇺🇸 US 🇨🇦 CA	Gray35AMP Fitment notes — GM GENUINE 13500114 Gray35AMP4-TerminalHigh Current Micro	View on Amazon

This table covers the relays that control the Starter Motor Control circuit. Typical signs include a click with no action, or a circuit that works only when you swap in a known-good relay. Swap with an identical relay in the fuse box before buying — it is the fastest test there is.

Steering Wheel Audio Control Switch

Brand	Part Number	Markets	Notes	Buy
GM GENUINE Fits: 2.7L L4 Turbocharged	13550480	🇺🇸 US 🇨🇦 CA	RightPremium Luxury Fitment notes — GM GENUINE 13550480 RightPremium LuxuryMain Infotainment Steering Wheel Control Base (Family 2, GB)Labeled 13550480, 13545470, 13541575Jet BlackForward Collision Alert (UEU)	View on Amazon
GM GENUINE Fits: 2.7L L4 Turbocharged	13550481	🇺🇸 US 🇨🇦 CA	RightV Model Fitment notes — GM GENUINE 13550481 RightV ModelRadio Control with V Mode GBLabeled 13550481,13545471Jet BlackForward Collision Alert (UEU)	View on Amazon

This table covers the Steering Wheel Audio Control switches. Typical signs include a function that works intermittently, or a click without the accessory coming on. Inspect the connector behind the switch; heat-damaged terminals will kill the new part too.

Traction / Stability Control Switch

Brand	Part Number	Markets	Notes	Buy
GM GENUINE Fits: 2.7L L4 Turbocharged	84941655	🇺🇸 US 🇨🇦 CA	Black Fitment notes — GM GENUINE 84941655 Black Stop/Start Engine Control System (KL9)	View on Amazon

This table covers the Traction / Stability Control switches. Typical signs include a function that works intermittently, or a click without the accessory coming on. Inspect the connector behind the switch; heat-damaged terminals will kill the new part too.

Turn Signal Switch

Brand	Part Number	Markets	Notes	Buy
GM GENUINE Fits: 2.7L L4 Turbocharged	13545218	🇺🇸 US 🇨🇦 CA	LABELED 13545218, 13539318Intelligent High Beam Control (TQ5) Fitment notes — GM GENUINE 13545218 LABELED 13545218, 13539318Intelligent High Beam Control (TQ5)Exc. Rear Fog Lamps (T79)	View on Amazon
GM GENUINE Fits: 2.7L L4 Turbocharged	13545219	🇺🇸 US 🇨🇦 CA	Labeled 13545219Except Intelligent High Beam Control (TQ5), Rear Fog Lamps (T79)	View on Amazon
WELLS Fits: 2.7L L4 Turbocharged	1S17946	🇺🇸 US 🇨🇦 CA	without Automatic High Beam	View on Amazon
WELLS Fits: 2.7L L4 Turbocharged	1S17947	🇺🇸 US 🇨🇦 CA	with Automatic High Beam	View on Amazon

This table covers the combination / turn-signal switches. Typical signs include a function that works intermittently, or a click without the accessory coming on. Inspect the connector behind the switch; heat-damaged terminals will kill the new part too.

Wiper / Washer Switch

Brand	Part Number	Markets	Notes	Buy
GM GENUINE Fits: 2.7L L4 Turbocharged	13545696	🇺🇸 US 🇨🇦 CA	Switch Activation Type: Pull,Push,Twist Fitment notes — GM GENUINE 13545696 Switch Activation Type: Pull,Push,Twist Except Pulse Moisture Sensitive Windshield Wiper System (CE1)	View on Amazon
GM GENUINE Fits: 2.7L L4 Turbocharged	13545697	🇺🇸 US 🇨🇦 CA	Switch Activation Type: Pull,Push,Twist Fitment notes — GM GENUINE 13545697 Switch Activation Type: Pull,Push,Twist Pulse Moisture Sensitive Windshield Wiper System (CE1)	View on Amazon
STANDARD MOTOR PRODUCTS Fits: 2.7L L4 Turbocharged	WP667	🇺🇸 US 🇨🇦 CA	Column Mountedwithout Rain Sensitive Wipers	View on Amazon

This table covers the Wiper / Washer switches. Typical signs include a function that works intermittently, or a click without the accessory coming on. Inspect the connector behind the switch; heat-damaged terminals will kill the new part too.

Wiper Motor Relay

Brand	Part Number	Markets	Notes	Buy
GM GENUINE Fits: 2.7L L4 Turbocharged	D1780C	🇺🇸 US 🇨🇦 CA	Black Fitment notes — GM GENUINE D1780C Black BLACK35AMP5 TERMINALHIGH CURRENT MICRO 280	View on Amazon

This table covers the relays that control the Wiper Motor circuit. Typical signs include a click with no action, or a circuit that works only when you swap in a known-good relay. Swap with an identical relay in the fuse box before buying — it is the fastest test there is.

Buying Electrical Switch & Relay Parts for a 2021 Cadillac CT4

On this vehicle, the switch and relay system covers the switches, relays and flashers that route power to everything the driver touches.

Match the engine first. Every electrical switch & relay part here is engine-specific; each row shows which engine(s) it fits.
Read the notes on each row for position, trim and spec qualifiers before you order.
Where labor overlaps, inspect the connector terminals behind any failed switch — heat damage there will kill the new part too.
Cross-reference the manufacturer part number against your old part or a service-manual listing.

Start with the largest groups on this page: Oil Pressure Sender / Switch and Hazard Warning Switch .

Frequently Asked Questions

How many electrical switch & relay parts fit the 2021 Cadillac CT4?

Our catalog currently lists 55 electrical switch & relay parts for the 2021 Cadillac CT4 across 28 subcategories and 10 brands, covering both the 2.0L L4 Turbocharged and the 2.7L L4 Turbocharged. Each part is matched to the engine(s) it fits.

Do electrical switch & relay parts differ between 2021 Cadillac CT4 engines?

Yes. Every electrical switch & relay part on this page is engine-specific. Each row shows which engine(s) it fits — use the filter at the top to hide the rest. If you're unsure which engine you have, check the emissions label under the hood or the 8th character of your VIN.

What are the signs of electrical switch & relay problems on a 2021 Cadillac CT4?

Common symptoms include accessories that work intermittently, a click without action, or one function dead while its fuse tests fine. If you notice any of these, identify the affected subcategory above and cross-reference the part numbers listed.

What should I replace at the same time?

Where labor overlaps, inspect the connector terminals behind any failed switch — heat damage there will kill the new part too.

What do the market flags (US, CA, MX) on each part mean?

They show the market for which the manufacturer published application data for that part — where the vehicle was first sold, not where the part was made. If your 2021 Cadillac CT4 was originally sold in the US, the safest choice is a part marked for the US market.

How do I make sure a part fits my 2021 Cadillac CT4?

First match the engine — each row shows which engine(s) the part fits. Then swap a suspect relay with an identical known-good one from the fuse box before buying — it is the fastest diagnostic there is. The notes column carries position and trim qualifiers where they apply.

Other Parts for the 2021 Cadillac CT4

Belt Drive Body & Lamp Assembly Brake & Wheel Hub Cooling System Drivetrain Electrical Electrical Bulb & Socket Electrical Connector Engine Exhaust & Emission Fuel & Air Heat & Air Conditioning Ignition Interior Steering Suspension Automatic Transmission Wheel Wiper & Washer

Electrical Switch & Relay Parts for Other Cadillac CT4 Years

2026 Cadillac CT4 2025 Cadillac CT4 2024 Cadillac CT4 2023 Cadillac CT4 2022 Cadillac CT4 2020 Cadillac CT4

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Manufacturer names, model designations and part numbers are used for identification and fitment reference only. AutoFactsDB is an independent catalog and is not affiliated with, endorsed by, or sponsored by any vehicle manufacturer displayed on this page.

Published by AutoFactsDB from manufacturer application data. How fitment is matched Report a fitment error