Can't pull the codes from service engine soon light 96 blazer

I folks, I'm a newbie to the chevy forums and just recently purchased a 96 blazer for my son. Well, the check engine light came on. Already having been familiar with this concept I ran by Autozone to pull the codes.

Here's the problem: When he hooked the ODBII to my blazer it came back with a link error. After trying several times and testing the ODBII on another vehicle we checked fuses and the pins of the connector in my dash. No luck. Anybody out there that can shed some light on what I should do next to get engine codes would be appreciated.

I will attempt to do most of this myself and only take it to a shop when I find that I can't find and/or fix the problem myself.

By the way. It does not seem to be idling rough (vacuum leak), but I'm not going to eliminate anything until I start to hear from some of you veteran owners.

I'm sorry I posted this here. I should have put it under general tech forums. If you think you can help me I'm going to post same question under there. I would appreciate any input you may have...

i replied to this at your other post..