I have a eclipse head unit and i bought the wires to change them for my gran marquis. Why is my fuse blowing?

I have an eclipse cd4000 head unit that I tried to install in my gran marquis. I bought the wiring harness for it so i didn't have to figure out how to hardwire the unit. I plugged it in, turned the car on, and nothing happened. It ended up blowing the fuse for my lights to, a 4A fuse. How can I install the head unit without blowing another fuse?I have a eclipse head unit and i bought the wires to change them for my gran marquis. Why is my fuse blowing?you have a hot wire gounded