Stock head unit to amp connection question?

I have a Kicker ZR360 amp and a "10 kicker comp sub, in a toyota T100 pickup with a stock head unit, the head unit doesnt have pre-amp outs so inorder to connect these can i splice a wire going to a rear speaker and conect it to a RCA cable and plug that into the pre-amp imput on my amp or do i have to get a Line out converter and go that route?Stock head unit to amp connection question?
With an amp that has high-level inputs, you can use a speaker tap. But you cannot run it into low-level inputs (RCA) without using a LOC. The speaker output impedance does not match properly and all you'll get is noise.