diff --git a/src/gl/dynlights/a_dynlight.cpp b/src/gl/dynlights/a_dynlight.cpp
index d2efbe991..860e86de0 100644
--- a/src/gl/dynlights/a_dynlight.cpp
+++ b/src/gl/dynlights/a_dynlight.cpp
@@ -235,7 +235,7 @@ void ADynamicLight::Activate(AActor *activator)
 		m_cycler.SetParams(float(m_Radius[1]), float(m_Radius[0]), pulseTime);
 		m_cycler.ShouldCycle(true);
 		m_cycler.SetCycleType(CYCLE_Sin);
-		m_currentRadius = (BYTE)m_cycler.GetVal();
+		m_currentRadius = m_cycler.GetVal();
 	}
 }
 
diff --git a/src/gl/dynlights/gl_dynlight.cpp b/src/gl/dynlights/gl_dynlight.cpp
index 18b255999..de05bb19f 100644
--- a/src/gl/dynlights/gl_dynlight.cpp
+++ b/src/gl/dynlights/gl_dynlight.cpp
@@ -167,6 +167,8 @@ FLightDefaults::FLightDefaults(FName name, ELightType type)
 
 void FLightDefaults::ApplyProperties(ADynamicLight * light) const
 {
+	auto oldtype = light->lighttype;
+
 	light->lighttype = m_type;
 	light->specialf1 = m_Param;
 	light->SetOffset(m_Pos);
@@ -179,6 +181,17 @@ void FLightDefaults::ApplyProperties(ADynamicLight * light) const
 	if (m_additive) light->flags4 |= MF4_ADDITIVE;
 	if (m_dontlightself) light->flags4 |= MF4_DONTLIGHTSELF;
 	light->m_tickCount = 0;
+	if (m_type == PulseLight)
+	{
+		float pulseTime = float(m_Param / TICRATE);
+
+		light->m_lastUpdate = level.maptime;
+		light->m_cycler.SetParams(float(light->m_Radius[1]), float(light->m_Radius[0]), pulseTime, oldtype == PulseLight);
+		light->m_cycler.ShouldCycle(true);
+		light->m_cycler.SetCycleType(CYCLE_Sin);
+		light->m_currentRadius = light->m_cycler.GetVal();
+	}
+
 	switch (m_attenuate)
 	{
 		case 0: light->flags4 &= ~MF4_ATTENUATE; break;
diff --git a/src/gl/dynlights/gl_dynlight.h b/src/gl/dynlights/gl_dynlight.h
index e8448890b..f71f0dfdf 100644
--- a/src/gl/dynlights/gl_dynlight.h
+++ b/src/gl/dynlights/gl_dynlight.h
@@ -33,7 +33,7 @@ EXTERN_CVAR(Bool, gl_attachedlights)
 
 class ADynamicLight;
 class FSerializer;
-
+class FLightDefaults;
 
 
 enum
@@ -91,6 +91,7 @@ struct FLightNode
 
 class ADynamicLight : public AActor
 {
+	friend class FLightDefaults;
 	DECLARE_CLASS (ADynamicLight, AActor)
 public:
 	virtual void Tick();
diff --git a/src/gl/utility/gl_cycler.cpp b/src/gl/utility/gl_cycler.cpp
index b6d160925..d79770bf3 100644
--- a/src/gl/utility/gl_cycler.cpp
+++ b/src/gl/utility/gl_cycler.cpp
@@ -83,13 +83,23 @@ FCycler::FCycler()
 //
 //==========================================================================
 
-void FCycler::SetParams(float start, float end, float cycle)
+void FCycler::SetParams(float start, float end, float cycle, bool update)
 {
-	m_cycle = cycle;
-	m_time = 0.f;
-	m_start = m_current = start;
+	if (!update || cycle != m_cycle)
+	{
+		m_cycle = cycle;
+		m_time = 0.f;
+		m_increment = true;
+		m_current = start;
+	}
+	else
+	{
+		// When updating and keeping the same cycle, scale the current light size to the new dimensions.
+		float fact = (m_current - m_start) / (m_end - m_start);
+		m_current = start + fact *(end - start);
+	}
+	m_start = start;
 	m_end = end;
-	m_increment = true;
 }
 
 
diff --git a/src/gl/utility/gl_cycler.h b/src/gl/utility/gl_cycler.h
index 42effce34..bcff7e9de 100644
--- a/src/gl/utility/gl_cycler.h
+++ b/src/gl/utility/gl_cycler.h
@@ -22,7 +22,7 @@ class FCycler
 public:
    FCycler();
    void Update(float diff);
-   void SetParams(float start, float end, float cycle);
+   void SetParams(float start, float end, float cycle, bool update = false);
    void ShouldCycle(bool sc) { m_shouldCycle = sc; }
    void SetCycleType(CycleType ct) { m_cycleType = ct; }
    float GetVal() { return m_current; }