I have a PAC RP5-GM11 installed on my grand prix, and the steering wheel controls have worked well for a few years now, until I installed a rear view cam to run to my Kenwood Excelon DDX6906S head unit.
Cam works well, ran sensor wire from my deck as I did not see one coming from the PAC module.
Now the steering wheel control do not work anymore, and when I open the door the radio stays on, when before it did not.
I am not sure if the PAC interface can fail, but still pass all audio through, sounds plausible..
What would stop the steering wheel controls and the ACC at the same time?
I'd think clock spring, or ignition switch, but the switch is pretty new...
I tried unhooking all wires to the cam to rule it out, and it changes nothing...
Everything was wired correctly before, and all wiring is in tact, I spent 2 hrs working on that harness/interface when I got it...

What head end unit was in it before the Excelon?

It was factory, everything always worked fine.
I paused the radio yesterday, went in the store, came out and after getting in the car and shutting the door, the music un-paused.. :? lol
I am not sure what else it could be but a failed PAC interface...
Tried resetting it and no changes, almost looks like it is not lit up on its lil red led area anymore, that or it is a lot fainter...