<REQ> ADL pin assignments 1991 6.2L

[monksblood]

1991 chev silverado, 6.2 diesel

I have found what I think is is my ADL or diagnostic connector. The pins don't match up to what my chilton manual shows. I would have upped a drawing of what I have but attchments are disabled.
I am going to try to describe what I have. The hole shape from left to right with a number if a pin is there and a x if there is no pin

oblong (top row) 123x45 round hole
(bottom row) 67xxxx

the shape of the connector is the same as the book and it is the only one under the dash that I can see. This one is attached under the dash console where it is easy to get at.

I figured that the pin assignment from the Chilton manual was pretty close so I tried grounding pins 1 & 2 but could not get the service engine light to blink

Pin assignment from chilton book

oblong hole (top hole) FExCBA round hole
(bottom row) GHxxxM

My service engine light has been coming on intermittantly and I want to extract the code that is causing this before I start doing all the time consuming work of checking connections and wires