Did a little racing last Sunday(Autox).

Here's my problem. On the 4th run i notice that the car is running warmer than normal. Line back up in stagging and open the hood. Nothing is out of place so i spray the radiator down with water. Cools while driving, but as soon as i get back to stagging, the temp jumps. The cooling fan would not come on. Talked to my mechanic and he said that there should be a fan relay on the radiator itself. Did a GSR radiator swap yesterday with a high flow cooling fan. Did not have a relay on the original radiator or the swap. Where is this relay?? Not having a cooling problem now, but the fan still does not run when hot. 94 Civic Coupe DX D15.