Does anyone have instructions on taking out the factory unit and installing an aftermarket unit? I also have to run a backup camera to the rear and GPS antenna to the top. I am hoping that since I have roof marker lights the GPS antenna will be easy. I'm going to try all this tonight I'll try to take pics as I go. Any info would be great.

 

the center console just pops off and the unit has 4 screws which u need a socket wrench and then just pulls out. its a snap

 

Yeah I figured it out. Its a very tight fit you feel like you are going to break something.

 

So do you need a special wiring harness for the onstar?
I look on crutchfield and they do not have my harness and its a pretty new alpine unit.
Also I have sirius plug and play unit can use the same antenna for the xm for that?

 

The adapter needed will depend on your factory system. A Data bus interface is necessary to correctly maintain system issues like GM sound alerts, and Onstar applications. The Axxess GMOS-1 and PAC GMOS-1 are both used for non amplified systems. Use the Axxess GMOS-4 Or PAC GMOS-4BOSE for factory amplified vehicles.


Don't forget to purchase an install kit, and an antenna adapter for your head unit. Factory GM antenna inputs are smaller than most. The above mentioned kits are plug and play for easy install. You may want to try entering the product codes on eBay for a better deal, Crutchfield can get costly.

Serius and XM are now the same company, but I am not sure on that antenna. If the cap plugs into the antenna input" I think its green or yellow", you should be good. Older models required power. I would not chance it unless you first request information from the manufacturer.

 

So how can I figure out what system I have?
Also Im guessing mine will still be using the factory amps since Im leaving the door speakers and all in.Right?

Is this whathttp://cgi.ebay.com/BOSE-Stereo-Install-Wire-Harness-Hummer-H3-H3T-07-2007_W0QQitemZ350178024097QQcmdZViewItemQQptZLH_De faultDomain_0?_trksid=p3286.m20.l1116 you are talking about? And will this fit an alpine unit?

 

The quickest way to tell if your truck is amplified is by looking in your rear hatch area. If you have one side pocket under the window and the other side has a mesh breather panel you have a factory monsoon system with a subwoofer. If your truck has two storage pockets, one on either side, chances are you only have a standard deck with about 12watts of power to each speaker. Another way is to look behind the factory radio. I think there is a factory set of pre-amp RCA outputs. This is one of the reasons for the adapter.

Whether you change your factory radio or not, buying newer door speakers is always a good idea. Factory speakers are often paper and will wear quickly. A factory amp can provide clean sound from a new head unit, or the new unit itself will have more power than any factory head unit alone would deliver. You win both ways. Replacing factory speakers will allow a cleaner fuller sound, plus they are not a difficult install on the H3. Replacing the sub is another issue all together. Most people just want a bit more sound with some added clarity, and better options from the radio. Adding a new head unit and door speakers will do the trick nicely.

 

O ok I got you. So I have the the 2 pockets so I dont have the sub already in it.
I use to have a mazdaspeed mx-5 and the bose in it you had to change everything without one piece it wouldnt work. So if I wanted a new head unit i had to change speakers amps the whole works.Ill search ebay for the adapters. I just dont want to come across that again cause it was a pain but thanks for the help i appreciate it.