as above i removed my head unit but when i went to put it back in it keeps blowing the 15amp fuse in the engine fuse box!!
i have taken it out before and put it back in with no problems like this

so what could be causing this????

 

Have you mixed the power feed and earth?

Get a multimeter and check, check that you havent left any wires liable to short against anything as you push the unit home.