Here is a link on how to install a wiper delay setup on our econolines. It's for f100's but it will work on econolines.
Eric
http://www.fordification.com/bumpwiki/index.php?title=How_to_Install_a_'78-'79_Factory_Wiper_Delay_Setup
Eric
http://www.fordification.com/bumpwiki/index.php?title=How_to_Install_a_'78-'79_Factory_Wiper_Delay_Setup