question about L.O.C. (line output converter)

When connecting my amp and subs to my factory deck with my L.O.C. can i... just connect thru my rear speakers or do i have to hook front and rear? there are inputs for both...

Thanks in advance for the comments and advice. (scosche output converter FAI-3A)

You only need one set, make sure you use both speakers though

Also, the FAI-3A found at walmart really *****. Get an active LOC like the LC2i or Cache

I would recomend getting one of the Audio Control Loc's I had the Lc6ci and except that I wanted to get a few options that were not really available without HU swap I was impressed. You only need the one signal to respond to your question. Make sure its a full range signal tho.

Thanks guys, ya i got the walmart special lol. Best buy didnt have any in stock coulda shopped around online i guess... Plannin on buyin a new HU soon so ill jus deal wit this one loc for now and wire straight to new HU when i get one