Hyundai sante fe 2001 V6.. I replaced the heater controls (as there was a problem causing fuses to blow when you turned the fan control on), So thats problem 1 solved, Now.. When i turn the key it blows a fuse straight away even with the heater controls unplugged, I put a bigger fuse in and it started smoking so do you think its a connection in my fuse box and i need to replace the complete fuse box unit??

No I think there is something else on the circuit which is bad, and you replaced the wrong thing. In other words the heater controls were not blowing the fuse and the fuse box is doing its protection job, at least was until you melted it from putting the wrong fuses in it. Adventures such as this show why it sometimes saves time and money to simply pay someone who knows what they are doing to do it right the first time. Electrical systems today are so complex that someone with all the info and tools at had is required to fix them.

On the back of the panel you will find one side of the fuse is connected to 12 volts, the other side has some connectors, or has one connector wire which takes the 12V to a set of connections. You have to disconnect each of those connections, one at a time, and replace the fuse until you find the one which actually has the component which is drawing too much current for the fuse. Then you either live without that component or go buy another one.