diff --git a/function/modules.py b/function/modules.py
index a7176cc..c734ac1 100644
--- a/function/modules.py
+++ b/function/modules.py
@@ -313,4 +313,5 @@ class motion_sensor_light(common_base):
 
     def cyclic_task(self, cyclic_task):
         min_value = 10 if self.motion_detected() else 0
-        self.set(self.KEY_TIMER, max(min_value, self[self.KEY_TIMER] - cyclic_task.cycle_time))
+        if self[self.KEY_TIMER] != 0:
+            self.set(self.KEY_TIMER, max(min_value, self[self.KEY_TIMER] - cyclic_task.cycle_time))