Thread: 2004 Grand Prix Monsoon HU Replacement Questions

Hey guys recently my head unit has been acting up. It will turn on when the car is off periodically and drain the battery. Today I had to get jump the car. Often it also stops responding to button inputs. Anyway I want to replace it with a different unit. I can find used units on ebay for 90ish or I could replace it with an aftermarket one with my tax return.

I've seen a few posts on what adapter to buy(GMOS-04) but they all seem to apply to cars with onstar which I do not have. I just want to confirm what I need to get.

I have the Monsoon XM radio 6 CD head unit without onstar. Keeping the chimes does not matter much nor does the steering wheel volume controls, although it would be a nice bonus.

Any help is appreciated.

Cheers.

Originally Posted by industrialfish

The OnStar part is a separate plug on the GMOS-04 harness so just don't need to plug it in.

Originally Posted by simbah

If you wish to keep your Monsoon amp then you will need the GMOS-04 adapter. If you decide to go the aftermarket amp route then the GMOS-01 is the adapter you will need. Regardless of whether you have Onstar or not. If you decide to get another factory radio then you will have to have that radio programmed to fit your car at a Dealership about $75.

Thank you, both of you. So looks like i will be going the GMOS-04 route than.