diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1dfeed76..a9b4f3ee 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -86,6 +86,7 @@ will consitute of a breaking change warranting a new major release:
 - Some smaller logic fixes in the TM store base class
 - Fixed usage of C `abs` instead of C++ `std::abs`, which results in MTQ commands not being
   scaled correctly between 1Am² and 0.2Am².
+- Prevent spam of TCS controller heater unavailability event if all heaters are in external control.
 
 # [v2.0.5] 2023-05-11
 
diff --git a/mission/controller/ThermalController.cpp b/mission/controller/ThermalController.cpp
index 7133dd88..4c475e35 100644
--- a/mission/controller/ThermalController.cpp
+++ b/mission/controller/ThermalController.cpp
@@ -1631,13 +1631,18 @@ bool ThermalController::selectAndReadSensorTemp(HeaterContext& htrCtx) {
 bool ThermalController::chooseHeater(heater::Switch& switchNr, heater::Switch redSwitchNr) {
   bool heaterAvailable = true;
 
-  if (heaterHandler.getHealth(switchNr) != HasHealthIF::HEALTHY) {
-    if (heaterHandler.getHealth(redSwitchNr) == HasHealthIF::HEALTHY) {
+  HasHealthIF::HealthState mainHealth = heaterHandler.getHealth(switchNr);
+  HasHealthIF::HealthState redHealth = heaterHandler.getHealth(redSwitchNr);
+  if (mainHealth != HasHealthIF::HEALTHY) {
+    if (redHealth == HasHealthIF::HEALTHY) {
       switchNr = redSwitchNr;
       redSwitchNrInUse = true;
     } else {
       heaterAvailable = false;
-      triggerEvent(tcsCtrl::NO_HEALTHY_HEATER_AVAILABLE, switchNr, redSwitchNr);
+      // Special case: Ground might command/do something with the heaters, so prevent spam.
+      if (not(mainHealth == EXTERNAL_CONTROL and redHealth == EXTERNAL_CONTROL)) {
+        triggerEvent(tcsCtrl::NO_HEALTHY_HEATER_AVAILABLE, switchNr, redSwitchNr);
+      }
     }
   } else {
     redSwitchNrInUse = false;