TM 9-2320-364-20-3 2-2912 6.  FAN SPEED DOES NOT LOWER FROM HIGH SPEED TO LOW SPEED (CONT). 3. Is continuity measured between connectors MC59, terminal B and MC128, terminal A? Repair wire 1933 (see schematic Fig 2-67) or notify DS Maintenance. Verify repair, go to Step 19 of this Fault. YES NO Heater blower motor operates,   indicating CB15 OK. Fan operates at low speed with   hydraulic selector switch in   AUTO or CRANE/SRW   position. Fan operates at low speed with   throttle position switch   depressed. Wire 1933 between MC59 and   MC128 faulty. Wire 1932 between MC59 and   MC61 faulty. Wire 1932 between MC61 and   MC128 faulty. Temperature sensor faulty. Wire 1538 faulty. Wire 1435 from fan controller   faulty. Wire 1935 or 1936 between   MC59 and MC76 faulty. Temperature switch faulty. KNOWN INFO POSSIBLE PROBLEMS TEST OPTIONS REASON FOR QUESTION Continuity test. STE/ICE-R #91. If wire 1933 between connectors MC59 and MC128 is loose, faulty or shorted to ground, fan controller will automatically operate fan at high speed. 4. Repair wire 1932 (see schematic Fig 2-67) or notify DS Maintenance.  Verify repair, go to Step 19 of this Fault. YES NO Heater blower motor operates,   indicating CB15 OK. Fan operates at low speed with   hydraulic selector switch in   AUTO or CRANE/SRW   position. Fan operates at low speed with   throttle position switch   depressed. Wire 1933 between MC59 and   MC128 OK. Wire 1932 between MC59 and   MC61 faulty. Wire 1932 between MC61 and   MC128 faulty Temperature sensor faulty. Wire 1538 faulty. Wire 1435 from fan controller   faulty. Wire 1935 or 1936 between   MC59 and MC76 faulty. Temperature switch faulty. KNOWN INFO POSSIBLE PROBLEMS TEST OPTIONS REASON FOR QUESTION Continuity test. STE/ICE-R #91. If wire 1932 between connectors MC59 and MC61 is loose, faulty or shorted to ground, fan controller will automatically operate fan at high speed. WARNING Is continuity measured between connectors MC59 terminal A and MC61 terminal A? Read   WARNING on Page 2-2913