Delegate Control not showing on Master Page in SharePoint 2013

This issue occurred because the value for ControlSrc in Elements.xml is not correct. The path to the user control must point to the file in the folder structures for SharePoint 2013(15 Hive)

Refer to the .cs file for the webpart which has the path to the user control file generated by Visual Studio. Generally the path must start with “~/_ControlTemplates/15/…”

Add code behind to SharePoint 2013 master page

One way is to add delegate control to master page. Follow the article: http://www.sharepointpals.com/post/Step-by-step-procedures-to-create-a-delegate-control-in-SharePoint-2010

However for some reason, it’s required to set ControlSrc to “~/_ControlTemplates/15/…” or else the control won’t be used.