Honestly, it may simply be a key on timer. I know it was to be replaced when it "expired." I do not know how the output was configured.

I have an '82 or '83 Camaro service manual at home. I will try to remember to check for more information.

If I searched "E Cell Program Modifier", I just got "Do you mean Excel Programming" !
Sometimes I long for the days when a search engine displayed what you asked for rather than asking if you wanted what it displayed.