diff --git a/dev/MRTCore/mrt/Microsoft.Windows.ApplicationModel.Resources/src/Microsoft.Windows.ApplicationModel.Resources.idl b/dev/MRTCore/mrt/Microsoft.Windows.ApplicationModel.Resources/src/Microsoft.Windows.ApplicationModel.Resources.idl
index 3c78578a64..74d67e2001 100644
--- a/dev/MRTCore/mrt/Microsoft.Windows.ApplicationModel.Resources/src/Microsoft.Windows.ApplicationModel.Resources.idl
+++ b/dev/MRTCore/mrt/Microsoft.Windows.ApplicationModel.Resources/src/Microsoft.Windows.ApplicationModel.Resources.idl
@@ -11,7 +11,7 @@ namespace Microsoft.Windows.ApplicationModel.Resources
     runtimeclass ResourceLoader
     {
         ResourceLoader();
-        ResourceLoader(String fileName);
+        ResourceLoader(String resourceMap);
         ResourceLoader(String fileName, String resourceMap);
 
         static String GetDefaultResourceFilePath();
diff --git a/dev/MRTCore/mrt/Microsoft.Windows.ApplicationModel.Resources/src/ResourceLoader.cpp b/dev/MRTCore/mrt/Microsoft.Windows.ApplicationModel.Resources/src/ResourceLoader.cpp
index 893d2b3464..f0b7c1ebf9 100644
--- a/dev/MRTCore/mrt/Microsoft.Windows.ApplicationModel.Resources/src/ResourceLoader.cpp
+++ b/dev/MRTCore/mrt/Microsoft.Windows.ApplicationModel.Resources/src/ResourceLoader.cpp
@@ -18,10 +18,13 @@ ResourceLoader::ResourceLoader()
     SetDefaultContext();
 }
 
-ResourceLoader::ResourceLoader(hstring const& fileName)
+ResourceLoader::ResourceLoader(hstring const& resourceMap)
 {
+    hstring fileName;
+    winrt::check_hresult(GetDefaultPriFile(fileName));
+
     winrt::check_hresult(MrmCreateResourceManager(fileName.c_str(), &m_resourceManager));
-    winrt::check_hresult(MrmGetChildResourceMap(m_resourceManager, nullptr, L"Resources", &m_currentResourceMap));
+    winrt::check_hresult(MrmGetChildResourceMap(m_resourceManager, nullptr, resourceMap.c_str(), &m_currentResourceMap));
     SetDefaultContext();
 }
 
diff --git a/dev/MRTCore/mrt/Microsoft.Windows.ApplicationModel.Resources/src/ResourceLoader.h b/dev/MRTCore/mrt/Microsoft.Windows.ApplicationModel.Resources/src/ResourceLoader.h
index 29d6159418..b6589a306b 100644
--- a/dev/MRTCore/mrt/Microsoft.Windows.ApplicationModel.Resources/src/ResourceLoader.h
+++ b/dev/MRTCore/mrt/Microsoft.Windows.ApplicationModel.Resources/src/ResourceLoader.h
@@ -13,7 +13,7 @@ namespace winrt::Microsoft::Windows::ApplicationModel::Resources::implementation
 struct ResourceLoader : ResourceLoaderT<ResourceLoader>
 {
     ResourceLoader();
-    ResourceLoader(hstring const& fileName);
+    ResourceLoader(hstring const& resourceMap);
     ResourceLoader(hstring const& fileName, hstring const& resourceMap);
 
     static hstring GetDefaultResourceFilePath();