My '87 305 tpi IROC started to not idle correctly when cold (this problem was intermittent over a few weeks now just idles too low when cold and I have to foot the accelerator until the engine is warm enough to idle on its own)... so I went to do a self diagnostic test for trouble codes but the "12 code" doesn't even flash (nothing flashes) so the diagnose is not working... so both chilton and haynes say next to check all wire connections and vacuum hoses, so I did. I found exposed, corroded wires on connectors for burn off, MAFS and fuel pump relays, so I found the exact parts online for the 3 relays and connectors, no problem... further inspection I noticed this black connector (see attached pics) that obviously needed replacing so I cut it off thinking I'd splice in a new one... I've been searching online for hours for this thing, I have all elec. schematics but it does not indicate what this thing is.... one side has a lt blue and a blk wire, other side has a lt grn/blk and a blk wire. On top of this thing is a christmas tree style post that fit into a small metal bracket mounted on the passenger side firewall. I'm thinking it may be for the fog lights, which never worked, but I want to replace with the proper connector but... is it just a splice connector?? I took it apart and I see no fuses??? I'll show more pics of it apart... only 3 pics/post
Thanks!!

 

Pics after I took this thing apart... the black gunk seems to be some kind of dielectric grease

 

That seems to be the HVAC connector. Your best bet would be a junkyard.

 

Thanks BBLou. I still can't find it online so I will try the boneyard route.