GMC Forward Control P3500 (1985-1999) Shift interlock circuit

AUTO APPLY FUSE 19 BLK WIRE BRAKE/TRANSMISSION SHIFT INTERLOCK (BTSI) SOLENOID (ON STEERING COLUMN) BRN WIRE DK GRN/WHT WIRE ELECTRONIC BRAKE CONTROL MODULE (BELOW RADIATOR ON CROSSMEMBER) HOT IN RUN HOT IN RUN AND START I-3 FUSE 9 I/P FUSE BLOCK PARK/NEUTRAL POSITION AND BACKUP LAMPS SWITCH (LEFT OF TRANS) PNK WIRE PPL TO BODY BUILDER HARNESS TORQUE CONVERTER CLUTCH AND STOP LAMPS SWITCH (AT BRAKE PEDAL SUPPORT) YEL WIRE