93 850NA A2 OBD light on as soon as plugged in

[Clivus]

This is a new one, maybe, for you folks. I have been chasing an intermittent failure to start. Replaced fuel relay, fuel pump, injector seals, ECT. Thought I had it fixed until tonight.
I had previously had ECT codes even after replacing the ECT. I finally cut the wires and respliced. Since then, I've had no other 123 codes on A2 or A6.

I plugged the wire into A2 tonight and the light illuminated without any button press. If I pressed the button, the light would get brighter, but didn't respond as usual. Couldn't read, couldn't clear. The other ports responded as normal.

I'm praying this is a clue to what is finally wrong with this thing.