So... the only wires you should need for the DEQ are RCA's in and out (unless you're going line-level straight to the speakers, but in that case it's just standard speaker wire). What you might need a harness for is the head unit, and like Triathelete said, you should be able to get that at just about any car stereo shop, or you can try online at places like crutchfield.com or sounddomain.com. Does that answer your question, or am I misunderstanding what you are trying to do?