keyless trunk entry on 97 cutlass

[dreaded_hippie]

i have a 97 cutlass that came with a remote. the keyless entry works fine but it has 3 buttons. i tried using the 3rd for the trunk and it didnt work. i figured the battery were dying so i replaced it. tried it again. the keyless entry worked fine but still havin to use my key for the trunk. i then got under the trunk and looked under the lid to see if the red switch was on or off and its on. i figured it had to be on cause the button inside the car to open the trunk works. so anyways if you can help me in anyway to program my remote to open the trunk it would help me alot.... thanks