diff --git a/src/g_level.cpp b/src/g_level.cpp
index a1759cdce..f4d105125 100644
--- a/src/g_level.cpp
+++ b/src/g_level.cpp
@@ -150,7 +150,7 @@ CUSTOM_CVAR(Bool, gl_notexturefill, false, CVAR_NOINITCALL)
 
 CUSTOM_CVAR(Int, gl_maplightmode, -1, CVAR_NOINITCALL | CVAR_CHEAT) // this is just for testing. -1 means 'inactive'
 {
-	if (self > 5 || self < -1) self = -1;
+	if (self > 4 || self < -1) self = -1;
 }
 
 CUSTOM_CVARD(Int, gl_lightmode, 1, CVAR_ARCHIVE, "Select lighting mode. 2 is vanilla accurate, 1 is accurate to the ZDoom software renderer and 0 is a less demanding non-shader implementation")