Could it be an idle load compensator,for an A/C equipped vehicle? My 82 Caddy 1.6NA with A/C has provisions for 2 of these . The PO must have removed them,but the mounting brackets and electrical connectors are still present.Looks identical to the pic. The 81 Caddy 1.6NA w/o A/C that I used to own didn't have this setup. Both Caddys had upshift lights.
I'll check my caddy this weekend and see if I get power to the connector with the A/C ON. I'm wondering if these are still available,as I would like to replace mine,which are missing. Currently- My a/c needs a charge,just enough in the system for the compressor to run,but not enough for cold air. Hope to get to that soon.