Simple way to reduce 24vdc to 12vdc?

[belfert]

I have a voltage converter I got cheap on Ebay that converts 24 volt to 12 volt for stuff on my dash.  I have both 24 volt and 12 volt in the front electrical panel, but the 12 volt is not switched while the 24 volt is.  I could have rigged up a relay or something to switch the 12 volt, but I got the converter instead.