public Program()
{
  Runtime.UpdateFrequency = UpdateFrequency.Update100;    // Run Main() every 100 ticks, or about 1.3s
}

public void Main()
{
  checkThrusters();     // I didn't put the code directly into Main() so you can cut and paste below into any other PB
}

int minimumCount = 10;                // Minimum number of operating test blocks
string testTag = "Thruster";          // Can be any part of the test block's name (e.g. Thruster Left, Ion Thruster)
string activateTag = "Black Smoke";   // Can be any part of the effector blocks name

public void checkThrusters()
{
  var tbList = new List<IMyTerminalBlock>();
  GridTerminalSystem.SearchBlocksOfName(testTag, tbList);
  var working = tbList.Count();

                                      // This next section tests each block, and if it's not working(damaged, grinded down, turned off) takes it out of the "working" count.
  foreach (var tb in tbList)
    if (!((tb as IMyFunctionalBlock).IsFunctional))
      working--;

  GridTerminalSystem.SearchBlocksOfName(activateTag, tbList);
  foreach (var tb in tbList)
    (tb as IMyFunctionalBlock).Enabled = (working < minimumCount);    // Turns activate blocks on/off
}