Quote Originally Posted by mntnbiker View Post
Crutchfield is saying I need the GMOS-01. They also have a PAC RP5-GM11 listed as well for the steering wheel control along with the Metra 95-3527 dash kit and a Metra 40-GM10 antenna adaptor. Sounds like I need both the GMOS and PAC harnesses for this install?
Yup correct

GMOS-01 is what you need if you don't have the monsoon system to use a aftermarket CD player with the stock system.

GMOS-04 if the car has the Monsoon system.

The pac adapter is to maintain the steering wheel controls .