Swiftech uses a similar relay system on their watercooled kits (you can buy this from
Cooltechnica for $18, or from Swiftech for $17.25). if you click on product info, then watercooled kits, then on the installation guide for their "H202 LIQUID COOLING KITS - Dual fan series", it'll show how to set it up. it might help if you want to build one yourself...