What kind of fan controller are you using, you need one that slowly brings the fan speed up to 100 percent so you dont have that big amp surge at spin up or turn on. The cheap controllers turn the fans on at full power which causes blown fuses and arcing terminal connections, make sure all your connections are soldered, crimped terminals will eventually arc and blow fuses. oem electric fans are amp pigs, thats why i went with a flexalite black magic extreme #185 fan with an amp draw of 18 amps. I have a mild 340 hp motor so this fan serves me well. I can sit in traffic here in virginia and the temp gauge stays right at 198 degrees.