I have an 06 cts Cadillac with a sunroof which all of a sudden decides to stop opening. How or where can I fix it?

The dial can be tricky. Have you tried going through the positions slowly several times ? If that doesn't wake it up try pressing the dial firmly towards the roof. Its a button, not just a dial. The button resets the antipinch control. The fuse location is shown in the owner's manual. Power Sunroof Module J-Class fuse is located under the rear seat passenger side. You can easily pry up on the rear seat, designed to do so because of the fuse boxes. Then push the carpet forward a bit on the passenger side. The fuse box is right there, while you are there. Label the cover to the fuse box as to what side they belong to. They can easily be swapped and you not know it until the next time when you are trying to figure out the damn diagram... then you find out it's for the wrong side

OMG I wish I saw this 6 hours ago, I have tried everything, I spent the last 5 hours tracing the wires, checking every fuse and relay. My CTS has 144k on it, and a week ago I saw that the roof was not closed all the way. I replaced the motor, that didn't work, got a new switch and that didn't fix it. So I started checking everything. Then I saw this, bam! its working! The parts came with no instructions. I gave up about two hours ago, then I said let me look one more time. Never did I ever think the rotary knob was a button too. I push it and now its working again. I can't thank you enough. Rich from Kansas Aug 2018

Thank you so much!!!! May sound a little strange but i have a strong connection with sunroofs. Just got back in the car and pushed the dial up, damn if it didn't work!!!!!! Thanks a million!