I have a 08 Hummer H3 Adv. It has the monsoon system without onstar.

I am wanting to keep my factory headunit for now because i like the 6 disc changer.

What will be needed to hook it up?

I've hooked up systems with aftermarket head units, but never a factory one. Does the Monsoon have RCA plugs in the back to power the factory amp?
Is there anyway I can unhook the stock sub but the amp still power the door speakers?

Thanks in advance for all help.

 

You will need a Line Output Converter to give you RCA Outputs. The factory player will not have them. You can use the factory amp to make your connections. Since you are asking about unhooking the factory sub, Im assuming you're going to remove the rear side panel to get to it (that is where the factory amp is). Get a good LOC from a local stereo shop dont get a cheap one from wal-mart. It might cost you $20.

You can just unplug the factory sub after youve removed the panel. It has a harness going into it with the speaker wire that can be unplugged so it stops playing.