How do I hook up my car amp and sub using a 5 channel amp with a 2 Preamp head unit?

Question

I am trying to hook up a 5 channel amp to my front and rear speakers and hook up a sub. My head unit only has 2 preamps (Front, Rear/Subwoofer). The amp I am looking at has 3 inputs (front, rear, and sub). If I run RCA cables from my headunit to the front and rear inputs on the amp will I be able to run my sub off the amp to even tho I dont have a preamp sub wire coming from the headunit? If this doesnt work can anyone tell me a possible soultion? I am VERY confused!

Answer 1

spit your front preamps off the stereo and use the rear preamps for the sub or get a better headunit with enough outputs