Yes , Gm car's have this tool called a Plug Wire Puller which is used to pull the wireset off the plug. If you go into Autozone you could purchase this for like $4.00 to $15.00 depending on which one you want the better one or the cheaper one .
First you have to look at your taillight sockets and make sure they are not burned if they are well you need to replace it .For example if the socket is black inside you need a new one. Also if you go to any Autozone they would be more than happy to help you out with this issue . And if not well...