Volvo 850 I (1991-1997) Back-up lamps circuit

A/T BACK UP LAMP BACK-UP LIGHT SWITCH (ON TRANSAXLE) BLK WIRE BLU WIRE CENTRAL ELECTRICAL ENGINE COMPT) EXTERIOR LIGHTS CIRCUIT FUSE 27 GRY WIRE HOT IN RUN LEFT LOWER TAILLIGHT ASSEMBLY LEFT TAILLIGHT ASSEMBLY M/T NCA WIRE RIGHT LOWER TAILLIGHT ASSEMBLY RIGHT TAILLIGHT ASSEMBLY BACK- UP LAMP SEDAN TRANSMISSION RANGE SENSOR (ON TRANSAXLE) UNIT (LEFT REAR OF WAGON