1998 Questions for all other cars relay hot

My car is peugeot 306 which is not listed in make selection.

The problem with my car is with wiring. The connection between one pin of the the relay to the wire( -ve) is always hot that make the socket that holding it melt. The relay is which control the radiator fan. I have also once change the radiator fans because they both jammed last time. The problem only occurs at one relay f that control one fan.
When it worse(melting) one fan not working make the engine hot. I have to take the relay out and clean it to make it normal back.
I have change the relay once and the problem still arise.