TM 9-2320-363-20-1 Table   3-1. Troubleshooting    (Cont) Malfunction Test   or   Inspection Corrective   Action ELECTRICAL   SYSTEM   (CONT) Standard    Heater   Circuits   (Cont) Step 5. Disconnect lead    98T    from   heater   fan   motor.    Check    for   +12 VDC at   lead    98. . If   no   voltage    is   present,    replace heater    fan    high   relay (pages 4-197, 4-198). 3. HIGH SPEED DOES NOT OPERATE. Step 1. Disconnect lead    98L    from   heater   fan   control.    Check for   +12 VDC at connector (D) with heater fan control in   high   mode. . If   +12    VDC is   present,    go   to   step    2.    If   no   voltage is   present, replace heater   fan   control   (page 4-190). Step 2. Disconnect heater    fan    high   relay   from   connector. Check for   +12    VDC at connector 85    with    heater    fan   control   in   high   mode. . If   +12    VDC is   present,    go   to   step    3.    If   no   voltage is   present, repair    lead   98L    (page   3-2). Step    3. Disconnect heater    fan    high   relay   from   connector. Check    for   continuity between connector 86    and   ground. . If   continuity    is   indicated,    go   to   step    4.    If   no   continuity    is indicated, repair   ground   lead   (page 3-2). Step    4. Disconnect lead    98T    from   heater   fan    motor.   Check for   +12 VDC at   lead    98T. . If   no   voltage    is   present,    replace heater fan    high   relay (pages 4-197, 4-198). 4. MEDIUM-HIGH SPEED DOES NOT OPERATE. Step 1. Disconnect lead    98F    from   heater    fan fan    control    connector (F)   with   heater . If   +12 VDC is   present, control.    Check for   +12 VDC at   heater fan   control    in   medium-high mode. go   to   step    2.    If   no   voltage is   present, replace heater fan control (page 4-190). Step 2. Disconnect lead 98F from heater fan resistor block.    Check for   +12    VDC at lead    98F. . If   no   voltage    is   present, repair    lead    98F (page 3-2). 3-73