By-pass wiring Harnes for Cooling Fans

I am trying to solve an overheating problem where my cooling fans will not come on unless my AC is on. I had the same problem on my 1999 3.8 buick engine I fixed that problem by buying a wiring harness that plugged into the wiring harness of the fans. It was plug and play. I understand the racing guys were using this harness to cool their engines between drag races.

I bought this harness from a guy on Kijiji years ago now I need another Does anyone know the company that makes these units