1994 buick ltd custom service engine light help

So I am a little confused on how to do this. I read that you can put a jumper wire or a paper clip into port A and B and the service engine light should blink out the codes. I insert the wire into the ports and nothing pops up. Can anyone explain to me if I am doing it right. Or if it is the wrong port. Anythign would help.

This is 12 pin ALDL?

Are there pins in the "A" and "B" slots?

https://encrypted-tbn1.gstatic.com/images?q=tbn:ANd9GcQ25uVuLu-fZw4cmUZ949_3YdNxTJq7jKjUBxYLgr4z1oDYP-Tqvg