Light help with century 3.3

Well, My mom has a 1992 Buick Century custom 3.3l.. She said that she would give me the car as long as I pay for parts and such. So Here is my problem. We put in a new altenator, and drove it around for about 20 minutes because it had'nt run in a while. Well now the taillights stay on sometimes and the left blinker stays on aswell (front and back blinkers dont blink!) My friend told me to check the relay because that might be the problem. Well here is my question, Where is the relay? Its not in the fuse box, and I cannot find it under the hood. All help is greatly appreciated.
Thank you
Patrick