Black & Red connector on 1992-93 Delco radios??
What is the extra, or fourth, connector - black with a red tab fitted at the end - that is located almost directly below the normal 20-pin three (blue, white, black) harness connections on the 1992-93 Delco radios (in this case the 5 EQ/CD unit that was used for Pontiacs in 1992-93)? I know the later units also had a fourth connection but I've never seen a newer 1994 and up unit plugged into it'* original harness.
My uncle originally bought the car with just a basic AM/FM/Cassette and I don't think there was a place on that original radio for this fourth connection - although it was there when I replaced that basic unit with one of the rare 5 band EQ CD players so I simply plugged it into the available connection never thinking one way or another whether it was actually functional at least on my '92 Bonneville SE.
Now I have to remove my older Delco CD unit from my 1992 Bonneville SE (it died earlier this week and I'm not going to have it repaired just yet) and use a hardly used 1996 or 97 unit I got from a friend of mine. Since I don't have any radio controls on the steering wheel or the electronic climate control unit do I need to even find a harness that fits the green/dark green wires to the newer Delco unit or simply disregard it all together? Not sure exactly what this connection is for.
I'm asking only because in no wiring diagrams I've ever seen of either the 1992-93 or 1994 and up Delco radios is this added connection shown or mentioned.
I anyone else has replaced their 1992-93 unit with a more common 1994 and up Delco CD or Cassette unit what did you do with this extra connection?