TM 9-2320-363-20-1 Table    3-1. Troubleshooting (Cont) Malfunction Test   or   Inspection Corrective   Action 5. MEDIUM   SPEED    DOES NOT Step 1. Disconnect fan    control l Step 2. Disconnect l ELECTRICAL    SYSTEM   (CONT) Standard    Heater   Circuits    (Cont) OPERATE. lead  98E   from  heater  fan  control.  Check for   +12 VDC at   heater connector (C)   with   heater fan   control    in   medium mode. If   +12 VDC is   present, go   to   step    2.    If   no   voltage is   present, replace heater    fan   control   (page    4-190). lead    98E from    resistor   block.   Check    for   +12 VDC at   lead    98E. If   +12 VDC is   present, go   to   step    3.    If   no   voltage is   present, repair  lead   98E   (page   3-2). Step   3. Disconnect  leads  98E   and  98F   from  heater fan resistor block.    Check for continuity between contacts of   heater resistor   block. . If   no   continuity    is   indicated, replace resistor block    (notify   direct support    maintenance). 6. LOW SPEED DOES NOT OPERATE. Step 1. Disconnect fan    control l Step 2. Disconnect lead    98Y. l Step    3. Disconnect lead    98Y from    heater    fan    control.   Check for    +12 VDC    at heater connector (E)   with    heater    fan control in low   mode. If   +12 VDC is   present, go to step 2. If   no   voltage is present, replace heater    fan   control   (page 4-190). lead    98Y from    heater    fan    resistor   block.    Check for   +12 VDC at If   +12 VDC is   present, go   to   step    3.    If   no   voltage is   present, repair    lead    98Y (page    3-2). leads    98Y and   98E from    heater    fan    resistor block. Check    for continuity between contacts of   resistor    block. . If   no   continuity    is   indicated, replace heater fan    resistor    block (notify    direct    support    maintenance). 3-74