KNOWN INFO POSSIBLE PROBLEMS DIAGNOSTIC FLOWCHART TEST OPTIONS REASON FOR QUESTION KNOWN INFO POSSIBLE PROBLEMS TEST OPTIONS REASON FOR QUESTION TEST OPTIONS REASON FOR QUESTION NO YES NO YES NO YES PROTECTIVE CONTROL BOX/DISTRIBUTION BOX 2-236           Change 1 BATTERIES OK LEAD 57B GROUND OK PARKING BRAKE SWITCH BAD BODY HARNESS WIRES BAD GLOWPLUG CONTROLLER   BAD ALTERNATOR BAD HARNESS WIRE 2A BAD IGNITION SWITCH BAD HARNESS WIRE 29A BAD HARNESS WIRE 29C BAD PROTECTIVE CONTROL BOX/   DISTRIBUTION BOX BAD FROM 12 Page 2-234 GO TO 16, Page 2-238 IS LED 6 “ON”? REPLACE PARKING BRAKE SWITCH AND/ OR REPAIR WIRES IN BODY HARNESS 13 14 15 VISUAL If this LED is not ON, that would indicate a parking brake switch or brake warning light malfunction, or damage to body harness wires. VISUAL If this LED is not ON, that would indicate protective control box (PCB)/distribution box malfunctions. IS LED 5 “ON”? REPLACE PROTECTIVE CONTROL BOX/DISTRIBUTION BOX BATTERIES OK LEAD 57B GROUND OK IGNITION SWITCH OK HARNESS WIRE 29A OK HARNESS WIRE 29C OK DID LED 13 COME “ON” WITH PCB? IF ENGINE IS AT OPERATING TEMPERATURE, LED 13 WILL NOT COME ON. WITH DISTRIBUTION BOX, LIGHT WILL COME ON WHEN ENGINE IS AT OPERATING TEMPERATURE. GO TO A1, Page 2-248 1.TRY IT 2.VISUAL If this LED is not ON, that would indicate either malfunctioning ignition switch, damaged harness wires 29A and 29C, or malfunctioning protective control box (PCB)/distribution box. TM 9-2320-280-20-1 PARKING BRAKE SWITCH   BAD BODY HARNESS WIRES BAD GLOWPLUG CONTROLLER   BAD ALTERNATOR BAD HARNESS WIRE 2A BAD PROTECTIVE CONTROL BOX/   DISTRIBUTION BOX BAD KNOWN INFO POSSIBLE PROBLEMS PARKING BRAKE SWITCH   BAD BODY HARNESS WIRES BAD GLOWPLUG CONTROLLER   BAD ALTERNATOR BAD HARNESS WIRE 2A BAD PROTECTIVE CONTROL BOX/   DISTRIBUTION BOX  BAD BATTERIES OK LEAD 57B GROUND OK IGNITION SWITCH OK HARNESS WIRE 29A OK HARNESS WIRE 29C OK