GMC Forward Control P3500 (1985-1999) Backup lamps circuit, commercial chassis

A/T BRN WIRE HOT IN I/P FUSE BLOCK LT GRN WIRE M/T PARK/NEUTRAL POSITION (PNP), BACKUP LAMP SWITCH (LEFT SIDE OF TRANS.) PROVISION FOR LEFT BACKUP LAMP PROVISION FOR RIGHT BACKUP LAMP RUN WIRE TURN SIGNAL FLASHER (I/P FUSE BLOCK) TURN-B/U FUSE