That definitely looks like something that someone put in after the fact. If its going to your fans i would try and troubleshoot the stock fan circuit and relays to see if its working or not. This could have been something where it stopped working and the previous owner could have put his own type of circuit in there to control the fans. Do you have any toggle switches anywhere that your not sure what they do? I've seen people wire them to a switch before so they could only turn them on when the car started getting hot but I've seen people wire them to run all the time as well. However it is though if its hooked to your fans i would start there. If you don't have them you can search on the site here and find the factory service manual to help you trace the circuit. Good luck