ALDL connector?

Hello, The connection is located under the driver dash and looks like this.....

This guide can help https://www.2carpros.com/articles/buick-cadillac-chevy-gmc-oldsmobile-pontiac-gm-1983-1995-obd1-code-definitions-and-retrieval-method Please run down this guide and report back.

I have a ob1 connector but everyone I took it to that had the OB1 tester could not get the code from the computer, it kept saying "connect to the computer failed". What could cause this and how would I fix it? Is there another way to get the code from the computer via OB1 connector?

a paper clip corssed between A & B wil get it but if there is a connection problem that may be why or a blown fuse. turn key on and count flashes of service light it will flash three times for each flash lie 1 then 2 is a codes 12 which is normal.

i have a 1990 pontiac grand am. local parts store read code and said to replace ecm. a friend said to remove chip from old one and put it on new one. someone else said i had to reboot computer after installing new one. can i get the truth?

Replacement ECM's are generally sold without PROM chip. You must remove old PROM from ECM and install in replacement ECM.
A small cover on ECM houses the PROM and gently remove old PROM and install on new ECM. Make sure not to bend the small pins on PROM chip.

This is all done with battery disconnected. When you install the new ECM, reconnect battery and ECM will "relearn" correct parameters. It will do this over a period of a few days of normal driving.