Here is a brand new original GM Sunroof Switch for your 2003 CTS Caddy.
If your sunroof is starting to act up : not completely closing, oscillating, opening on it's own etc etc - then most likely it is a faulty switch.
03 CTS' are prone to sunroof problems due to worn or faulty switch's. Prevent your expensive seats and interior from getting wet and damaged from a roof opening unattended as is known to happen !
Here is a brand new switch to replace your worn switch or to have on-hand for "just in case" when your existing switch becomes faulty.
Please do not ask me to call you or for my phone number. I wil respond to all email and answer any questions - thank you !