TM 10-3930-664-24 i. Use the GO, NO-GO flowcharts for testing.  As you become more familiar with the test procedures, you can use the flip cards on the VTM.  Prior to testing, make the following pre-test inspections: (1) Check fan belt for proper tension.   Replace cracked or frayed belts. (2) Check for proper engine oil level.   Add oil as necessary. (3) Check that the fuel tank has enough fuel for testing. (4) Check for proper engine coolant level.   Add coolant as necessary. (5) Check  that  the  battery  is  in  good  condition.    Check  for  low  electrolyte  level  and  add  distilled  water  as required. (6) Check that emergency steering pump is turned off when required by testing. j. VTM Confidence Test.  This procedure provides an overall check of the VTM and should be run before and after each use to assure accuracy of results. NOTE If VTM fails to display correct readouts, refer to STE/ICE manual for fault isolation. (1) Run confidence test as follows: (a) Set TEST SELECTOR switches to 66. (b) Press and release TEST button. (c) Wait for display to show 0066. (d) Set TEST SELECT switches to 99. (e) Press and release TEST button. (2) Observe the following display readouts: (a) Display shows 0099. (b) Display blank. NOTE When performing step (c), observe display and verify that all segments of display are on. (c) Display shows 8.8.8.8.   If any segment of display is not working, refer to STE/ICE manual for repair instructions for Digital Display Modules. (d) Display blank. 2-15