I might be blind, or Cadillac likes to hide things.
I want to play around with advancing the timing a little but from what I have read I need to jump A, B terminals (IIRC) on the ALDL to put it into set timing mode. Problem is I have yet to find the terminal on my car.
Did they hide it behind lower dash trim?

Makes me feel like a total noob even posting this.

 

I think it's under the dash near the center (under the radio, ashtray, that general area). There's definitely a port there, but it's covered by a plastic cover that clips into the plastic cover/sound insulator under the dash. Not 100% certain that it's the ALDL port, but there is a port there, at least on my '87 coupe and '89 sedan there is.

 

Ok thanks, i'll have another look. I have never had one that I wasnt able to locate.
Leave it to me to get the one they hid it in really well. Haha!

 

Found it. Thanks.
Was farther back towards the heat vents under/behind the ashtray.

 

Ok thanks, i'll have another look.