Well ,I think all of the bulbs to the third brake light have to be out in order to stop cruise control. I had two out of four blown out and my cruise was still working fine..

Also, the shifting problem might be caused by a soft or pending code. Scan the computer even though the check engine light isn't on and I bet there is a pending code.

 

Hmm, so these guys are wrong?

https://www.chevyhhr.net/forums/prob...working-48459/

 

I had 1 out, no CC. Must be a sometimes thing.

 

Now thats odd. MY 2/4 bulbs were out for literally a year and a half. Had cruise the whole time. Is it a year to year thing?