Aftermarket Head Unit?

[coors]

I am looking at installing an alpine radio into my sport trac. The sport trac is a 2004 XLT with the stock sub. I know it may be a stupid question and all but, Do they make a wiring harness that will still include the stock sub in parallel the the aftermarket head unit?
I looked at it quite some time ago and could not find any products that specifically stated it would integrate the stock sub.

Thanks Guys!

 

[beachn974door]

Contact crutchfield. When I installed my JVC they sent me the wiring for the factory sub with it. Can not remember what the part number was for it but they can tell you.

 

[interscope8]

There is a wiring harness you plug from your head unit to be into the stock one. They have them at Autozone too.

I put my own sub and such in but know this because the guy at AutoZone kept trying to help me when I went in to pick up speaker wire and Im to polite to just walk away good luck