Hello There - I have read many posts, but I have to tell you that transferring a high-end stereo to my new H3 is quite a stressful chore. To begin with, I ordered an entire kit off of eBay for $120. It included a plastic mounting bracket, an antenna adapter and an On-star computer interface called NUCLEUS by American International. Removing the front dash is easy - just pull from the A/C vents and everything comes out REAL easy. Surprisingly, there are no screws AT ALL.The Install harness is easily crimped to the stereo harness and makes the head unit easy to install. The problem I am having is with the Onstar volume. Though the stereo mutes and the onstar continues to speak through the front speakers, the output is extremely low. I am contemplating ordering a $25 equalizer/amp from JCWhitney to amplify the Onstar Output.
Anybody else have any ideas? I have read that the pac-audio unit amplifies the Onstar when external speakers are connected, but I am stuck with the Nucleus unit. I tried connecting the wires to an RCA plug and then plugging it in to the amp, but the background noise was far too intense. Anyways, just wanted some opinions. Thanks!

 

Hi, I had a similar problem on mine. I had the standard radio, and then upgraded to the Navigation system. When I tried to use my phone and onstar the volume was so low I could hardly hear. I went back to the dealer and they had no clue. After reading a few posts here I found out that inorder to use the naviation you have to have the monsoon sterero or the upgraded stereo with the amp in the rear quarter. I think thte standard radio had a built in amplifiier and the navigation doesnt. So to answeryou question, I think you're right, if you add an amplifier after the radio the volume on the onstar will be lowder, this is what I was thinking of doing to solve a similar problem I have from adding the navigation.

 

The PAC audio has a little junction box. On that box there is a little screw that adjusts the onstar volume. Probably doesn't help you but my volume was very low. I was able to adjust the volume up with that little screw. Good luck!

 

Hi There - I continued the install with the American International "NUCLEUS" computer. I bought this before I found out that the PAC computer is probably better. For those of you that don't know - there is no Accessory 12V connection in the stereo wiring. The American International "Nucleus" or PAC "OS-2" interface decodes a computer signal that tells it when to switch the 12V accessory/ignition power on. Apparently, the PAC interface has a built-in amplifier that will power a separate external speaker for the On-Star sound when wiring a separate amplifier. The American International "nucleus" does not have the amplifier, so I bought a cheap amp from JCWhitney and an external speaker to accomplish this task. Be prepared to purchase 3-4 RCA ground Loop Isolators to reduce the engine noise when you go this route. If you are running an AUX connection for your IPOD or XM receiver, or your amplified OnStar line, you might need 2 of these on the line to reduce the engine noise (it is ridiculous). If you are using the "nucleus" interface, you will also want to hard wire the constant 12V power to the pre-interface connection. It has been quite a challenge! The PAC OS-2 features a built-in amp to power an efficient 4ohm speaker that will rebroadcast the OnStar - just remember to connect the mute wire (brown) to the receiver - Good Luck!!