X50A Engine Wiring Harness Junction Block Top View

Courtesy of GENERAL MOTORS COMPANY

Usage Table

No.	Device Label Name	Device Assigned Name	Rating	Description
Fuses
F1	NOT USED	F1UA	-	Not Used
F2	NOT USED	F2UA	-	Not Used
F3	NOT USED	F3UA	-	Not Used
F4	NOT USED	F4UA	-	Not Used
F6	ELM 7	F6UA	20A	K219 Lighting Control Module
F7	ELM 4	F7UA	20A	K219 Lighting Control Module
F8	NOT USED	F8UA	-	Not Used
F9	ELM 5	F9UA	20A	K219 Lighting Control Module
F10	ELM 6	F10UA	20A	K219 Lighting Control Module
F11	LRR/FRT SRR	F11UA	15A	B233B Forward Range Radar Sensor - Long Range (UGN)
F12	NOT USED	F12UA	-	Not Used
F13	WSW FRT	F13UA	15A	KR11 Windshield Washer Pump Relay
F14	WSW RR	F14UA	15A	KR6 Rear Window Washer Pump Relay
F15	REC BATT 2	F15UA	60A	X53A Body Wiring Harness Junction Block - Rear
F16	PSM	F16UA	10A	P25 Content Theft Deterrent Alarm
F17	EBCM BATT 1	F17UA	60A	K160 Brake System Control Module X400
F19	DC/AC INV	F19UA	60A	T1 Accessory AC and DC Power Control Module (KI4/KI5)
F20	IECR2	F20UA	60A	X51R Instrument Panel Wiring Harness Junction Block - Right
F21	NOT USED	F21UA	-	Not Used
F22	IECL BATT 2	F22UA	60A	X51AX Instrument Panel Wiring Harness Junction Block - Auxiliary (5W4/9C1)
F24	FUEL HTR	F24UA	40A	KR22 Fuel Heater Relay (LM2)
F25	REC BATT 1	F25UA	60A	X53A Body Wiring Harness Junction Block - Rear
F26	CAMERA WASH	F26UA	15A	Not Used
F27	HORN	F27UA	15A	P13 Horn
F28	HDLP RT	F28UA	20A	E13RA Front Headlamp - Right
F29	HDLP LT	F29UA	20A	E13LA Front Headlamp - Left
F30	ELM 3	F30UA	20A	K219 Lighting Control Module
F31	ELM 1	F31UA	20A	K219 Lighting Control Module
F32	NOT USED	F32UA	-	Not Used
F33	NOT R/C	F33UA	10A	K60 Column Lock Module
F34	NOT USED	F34UA	-	Not Used
F37	MISC BODY IGN 1	F37UA	15A	K38 Chassis Control Module (G96) K160 Brake System Control Module K212 Gear Shift Control Module P16 Instrument Panel Cluster Control Module P43 Forward Collision Alert Display (UEU-UV6) X400
F38	MISC BODY IGN 2	F38UA	10A	K219 Lighting Control Module M73A Front Seat Back Ventilation Blower - Driver (KQV) M73B Front Seat Back Ventilation Blower - Passenger (KQV) M73D Front Seat Cushion Ventilation Blower - Driver (KQV) M73P Front Seat Cushion Ventilation Blower - Passenger (KQV) T1 Accessory AC and DC Power Control Module (KI4/KI5) X401 (MBR)
F39	UPFITTER	F39UA	10A	W12FC Blunt Cut - Front Seat/Center Console (5W4/9C1) W12RCL Blunt Cut - Left Rear Cargo Trim (5W4/9C1)
F40	MISC IP IGN	F40UA	10A	A10 Inside Rearview Mirror (DD8/DRZ) E40 Air Heater (C3A) K36 Restraints Control Module X51AX Instrument Panel Wiring Harness Junction Block - Auxiliary (5W4/9C1)
F41	TRLR PRK LAMP	F41UA	20A	X88B Tow Vehicle Electrical Receptacle (Z82-U1D)
F42	T/LAMP RT	F42UA	10A	Not Used
F44	TIM/TRLR IGN	F44UA	15A	K68 Trailer Lamp Control Module (U1D-MBR) X88B Tow Vehicle Electrical Receptacle (U1D+MBR)
F45	SECD AXLE MTR	F45UA	10A	M26 Front Drive Axle Actuator (NP0/NQH)
F46	ECM IGN	F46UA	15A	K20 Engine Control Module
F47	TCM/TCCM/PTSQ/DEFC IGN	F47UA	15A	K69 Transfer Case Control Module (NP0/NQH) K71 Transmission Control Module K115 Reductant Control Module (LM2)
F48	NOT USED	F48UA	-	Not Used
F49	TRANS AUX OIL PUMP	F49UA	15A	G5 Automatic Transmission Auxiliary Fluid Pump (MQC)
F50	A/C CLTCH	F50UA	10A	Q2 Air Conditioning Clutch
F51	TCCM	F51UA	30A	K69 Transfer Case Control Module (NP0/NQH)
F52	FRT WPR	F52UA	30A	KR12B Windshield Wiper Motor Relay KR12C Windshield Wiper Motor Speed Control Relay
F53	NOT USED	F53UA	10A	Not Used
F54	T/LAMP LT	F54UA	10A	Not Used
F55	TRLR REV LAMP	F55UA	10A	X88B Tow Vehicle Electrical Receptacle (Z82-U1D)
F56	SADS	F56UA	15A	K19 Suspension Control Module (Z95)
F57	NOT USED	F57UA	-	Not Used
F58	STRTR MTR	F58UA	30A	KR27 Starter Relay
F60	PWR/TRN SNSR 2	F60UA	10A	B195A Nitrogen Oxides Sensor 1 (LM2) T19 Multifunction Power Supply Converter (LM2) K212 Gear Shift Control Module (LM2)
F61	ALC MAIN	F61UA	15A	K5 Vehicle Level Control Module (F47)
F62	DEFC BATT 2/CNST VENT SOL	F62UA	10A	K115 Reductant Control Module (LM2) Q13 Evaporative Emission Canister Vent Solenoid Valve (L84/L87)
F63	TRLR BRK	F63UA	40A	K67 Trailer Brake Control Module (JL1) W24 Blunt Cut - Trailer Brakes Provision -(Z82-JL1)
F65	NOT USED	F65UA	-	Not Used
F66	COOL FAN MTR LT	F66UA	50A	G10L Cooling Fan Motor - Left
F67	NOT USED	F67UA	-	Not Used
F68	ALC MTR	F68UA	40A	K5 Automatic Level Control Module (F47)
F69	STRTR PINION	F69UA	40A	KR27C Engine Restart Relay
F71	COOL FAN MTR LWR	F71UA	50A	G10LW Engine Cooling Fan Motor - Lower (LM2)
F72	COOL FAN MTR RT	F72UA	50A	G10R Engine Cooling Fan Motor - Right (L84/L87)
F73	TRLR STP/TRN LAMP LT	F73UA	10A	X88B Tow Vehicle Electrical Receptacle (Z82-U1D)
F74	TIM BATT 2	F74UA	30A	K68 Trailer Lamp Control Module (U1D)
F75	DEFC BATT 1	F75UA	30A	K115 Reductant Control Module (LM2)
F76	ELEC RNG BDS	F76UA	30A	K4 Running Board Control Module (B3L)
F78	ECM BATT	F78UA	15A	K20 Engine Control Module
F79	CABIN COOL PUMP 17W	F79UA	10A	G17 Heater Coolant Pump
F80	PWR/TRN SNSR 1	F80UA	20A	B136 Exhaust Particulate Matter Sensor (LM2) B195B Nitrogen Oxides Sensor 2 (LM2) B195C Nitrogen Oxides Sensor 3 (LM2) K111 Fuel Pump Power Control Module (LM2) R29 Fuel Filter (LM2)
F81	TRLR STP/TRN LAMP RT	F81UA	10A	X88B Tow Vehicle Electrical Receptacle (Z82-U1D)
F82	TIM BATT 1	F82UA	30A	K68 Trailer Lamp Control Module (U1D)
F83	FTZM	F83UA	30A	K111 Fuel Pump Driver Power Module
F84	TRLR BATT	F84UA	30A	X88B Tow Vehicle Electrical Receptacle (Z82)
F85	AUX WATER PUMP	F85UA	15A	M10 Charge Air Cooler Coolant Pump (LM2)
F86	PWR/TRN ECM 1	F86UA	30A	K20 Engine Control Module
F87	EVEN INJ/ECM	F87UA	20A	K20 Engine Control Module (L84/L87) T8B Ignition Coil 2 (L84/L87) T8D Ignition Coil 4 (L84/L87) T8F Ignition Coil 6 (L84/L87) T8H Ignition Coil 8 (L84/L87)
F88	O2 B SNSR / MAF / ECM / WRAF / BCV	F88UA	15A	B52D Heated Oxygen Sensor - Bank 1 Sensor 2 (L84/L87) B52F Heated Oxygen Sensor - Bank 2 Sensor 2 (L84/L87) B75 Mass Airflow Sensor K20 Engine Control Module Q97B Engine Flow Control Valve - Block (LM2)
F89	O2 A SNSR / EPWR / CNSTR PRGE / WRAF	F89UA	15A	B52C Heated Oxygen Sensor - Bank 1 Sensor 1 (L84/L87) B52E Heated Oxygen Sensor - Bank 2 Sensor 1 (L84/L87) Q12 Evaporative Emission Canister Purge Solenoid Valve (L84/L87) Q44 Engine Oil Pressure Control Solenoid Valve (L84/L87)
F90	ODD INJ / ECM	F90UA	20A	K20 Engine Control Module T8A Ignition Coil 1 (L84/L87) T8C Ignition Coil 3 (L84/L87) T8E Ignition Coil 5 (L84/L87) T8G Ignition Coil 7 (L84/L87)
F91	PWR/TRN ECM 2	F91UA	15A	K20 Engine Control Module (L84/L87)
F92	AERO SH	F92UA	10A	M96 Active Grille Air Shutter Actuator (VTI/WMI) M96B Active Grille Air Shutter 2 Actuator (WMI)
Relays
K5	NOT USED	-	-	Not Used
K18	DC/AC INV	KR202 Accessory AC and DC Power Control Module Relay	-	F19UA
K23	FUEL HTR	KR22 Fuel Heater Relay	-	R29 Fuel Filter (LM2)
K35	TRLR PRK LAMP	KR125 Trailer Parking Lamp Relay	-	F41UA
K36	RUN/CRNK	KR73 Ignition Main Relay	-	F33UA F37UA F38UA F39UA F40UA F44UA F46UA F47UA F48UA
K43	SECD AXLE MTR	KR203 Front Drive Axle Actuator Relay	-	F45UA
K59	A/C CLTCH	KR29 A/C Compressor Clutch Relay	-	F50UA
K64	STRTR MTR	KR27 Starter Relay	-	M64 Starter Motor
K70	STRTR PINION	KR27C Engine Restart Relay	-	M64 Starter Motor
K77	PWR/TRN	KR75 Engine Controls Ignition Relay	-	F67UA F85UA F86UA F87UA F88UA F89UA F90UA F91UA F92UA KR29 Air Conditioning Compressor Relay KR200 Engine Controls Sensor Supply Voltage Relay
Note: Relays listed below are non-serviceable Printed Circuit Board (PCB) relays and are internal to the block.
-	-	KR3 Horn Relay	-	F27UA
-	-	KR6 Rear Window Washer Pump Relay	-	G24 Windshield Washer Pump
-	-	KR11 Windshield Washer Pump Relay	-	G24 Windshield Washer Pump
-	-	KR12B Windshield Wiper Motor Relay	-	M75 Windshield Wiper Motor
-	-	KR12C Windshield Wiper Motor Speed Control Relay	-	M75 Windshield Wiper Motor
-	-	KR61 Trailer Backup Lamp Relay	-	F55UA
-	-	KR63L Trailer Stop/Turn Signal Lamp Relay - Left	-	F73UA
-	-	KR63R Trailer Stop/Turn Signal Lamp Relay - Right	-	F81UA
-	-	KR200 Engine Controls Sensor Supply Voltage Relay	-	F60UA F80UA