this info will be in the owners manual. you need to push a few buttons inside the car to get into programing mode for the fob settings. adding the new fob might have reset the fob's settings aka, lights on for so long, or not at all, horn beeps, or dont beep.

heres a link your manual if you no longer have the factory one. chrome-extension://oemmndcbldboiebfnladdacbdfmadadm/https://my.gm.com/content/dam/gmownercenter/gmna/dynamic/manuals/2006/pontiac/grand_prix/2006_pontiac_grand_prix_owners.pdf