Glow plug fuse keeps blowing up at startup?

I have 2.0 diesel santa fe and it keeps blowing up glow plug fuse, i have checked the glow plug relay and it seems ok, but what i have noticed is that there is 12V and 3.6V at glow plug relay and both of these voltages dont disappear i.e they even stay there when engine has started. To my knowledge one of them (dont know which one or may be both) has to disappear after enginve has started or atleast when glow plugs are warmed up. I have been tolled that there is Engine control relay some where (i don't know where) controls the glow plug but I can find where is it.

can some one help with this problem..