Alpine HU to factory sub?

[aperson]

Hey all, I recently put my CDA-9883 into my 2002 WRX wagon and want to know if there's a way to run RCA's to the factory sub until I get speakers and a real sub in about 6 months. What I'm trying to accomplish is to use the crossover built into the deck so I don't have bass going to the speakers. If anyone can provide a schematic of the factory sub's amp or tell me if there is anywhere I can add a line level input to the amp it would be greatly appreciated.

Thanks!

[2010wrxhatch]

yes you can do it, you need a RCA to speaker wire adapter, you can get at Radio Shack