I own a 2003 grand cherokee, the fan to the engine would not kick on, but the fan and the thermostat is less than a year old, where is the fuse box so i can check the fuses

First, I'd hot wire the fan to the battery and just make sure it's OK...I never assume something is working even if I replaced it twenty minutes ago. Your realy and any attending fuses should be located in the power distribution center neaqr the battery and there should be a label inside the cover to help with identification of that and any attending fuses. The temperature sensor feeds info to the computer which in turn activates the relay and turns the fan on...any malfunction along the way will cause it to not operaqte properly. Also check that the fan comes on with A/C operation.