diff --git a/CHANGELOG.md b/CHANGELOG.md
index 08f904a9..a74c99fd 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -27,6 +27,8 @@ will consitute of a breaking change warranting a new major release:
 
 - TMP1075: Set dataset invalid on shutdown explicitely
 - Small fixes for TMP1075 FDIR: Use strange and missed reply counters.
+- TCS controller: Last heater (S-band heater) was skipped for transition completion
+  checks.
 
 # [v6.0.0] 2023-07-02
 
diff --git a/mission/controller/ThermalController.cpp b/mission/controller/ThermalController.cpp
index 603a72ea..da508f33 100644
--- a/mission/controller/ThermalController.cpp
+++ b/mission/controller/ThermalController.cpp
@@ -1754,7 +1754,7 @@ void ThermalController::resetSensorsArray() {
 }
 
 void ThermalController::heaterTransitionControl(const HeaterSwitchStates& currentHeaterStates) {
-  for (unsigned i = 0; i < 7; i++) {
+  for (unsigned i = 0; i < heater::Switch::NUMBER_OF_SWITCHES; i++) {
     if (heaterStates[i].switchTransition) {
       if (currentHeaterStates[i] == heaterStates[i].target) {
         // Required for max heat period control