If certain it's coming from the PAC interface,
The Metra one is probably more quality and will not have the noise. It also comes with steering wheel control built i..see EDIT below.
Metra Online
Axxess GMOS-044 GM Factory Integration Interface Adapter
Edit: Sorry it DOES NOT have SWC like the PAC. You need the Metra AWSC to have button control.
http://www.metraonline.com/part/ASWC-1
The Metra one is probably more quality and will not have the noise. It also comes with steering wheel control built i..see EDIT below.
Metra Online
Axxess GMOS-044 GM Factory Integration Interface Adapter
Edit: Sorry it DOES NOT have SWC like the PAC. You need the Metra AWSC to have button control.
http://www.metraonline.com/part/ASWC-1