Index: firmware/App/Services/SystemComm.c
===================================================================
diff -u -r5459a8a8b011c5956feb83c14fa98091287be7ac -r5c8d32c848b9dbbdbb992a981efd97393444144d
--- firmware/App/Services/SystemComm.c	(.../SystemComm.c)	(revision 5459a8a8b011c5956feb83c14fa98091287be7ac)
+++ firmware/App/Services/SystemComm.c	(.../SystemComm.c)	(revision 5c8d32c848b9dbbdbb992a981efd97393444144d)
@@ -21,14 +21,15 @@
 #include "sci.h"
 #include "sys_dma.h"
 
-#include "DrainPump.h"
-#include "SystemComm.h"
 #include "Comm.h"
+#include "DrainPump.h"
+#include "Heaters.h"
 #include "Interrupts.h"
 #include "OperationModes.h"
+#include "SystemComm.h"
+#include "SystemCommMessages.h"
 #include "Timers.h"
 #include "Utilities.h"
-#include "SystemCommMessages.h"
 
 /**
  *  @addtogroup SystemComm
@@ -672,7 +673,8 @@
     if ( TRUE == didTimeout( timeOfLastHDCheckIn, HD_COMM_TIMEOUT_IN_MS ) )
     {
         hdCommunicationStatus.data = FALSE;
-        setHDOperationMode( 0, 0 );   // If HD off or not connected, consider HD mode is fault.
+        setHDOperationMode( 0, 0 );      // If HD off or not connected, consider HD mode is fault.
+        stopHeater( DG_TRIMMER_HEATER ); // If HD off or not connected, ensure trimmer heater is off.
     }
 }