i will see if he can get a better picture of the connector his dash is back together not sure if it can be pulled down. he lives a couple hours away and weather is an issue so he is not driving it. it seemed like a mystery that would be fun to research. at this time it seems it is not used i will learn if he has any performance issues.

this was something from corvette forum

(From what little I can find/understand the 1982 (with crossfire) has a vehicle speed sensor mounted on the back of the stock speedometer. This evidently sends a signal through a little yellow box to the fuel injection ECM. GM #: 25007278)

GM #25007278 this was the little yellow box with a connector that looked like it would plug into that connector in question

Thanks for all the help i will try to get more info have not been on here for awhile since getting a C5 you guys are always great

Bob

Well then...assuming that info is correct, it would appear that the part is an optical reader attached to the rear of the speedo head, that senses the revolutions of the speedo cable, then translates that into an electrical signal to the ECM. GM parts does NOT show that part number as valid for the '82 Corvette, tho. The mystery continues! 🧐

 if i get a better picture i let you know it might just be the courtesy light like i first thought but the picture of the socket not being clear and him giving me the 3 wires going to it that sent me down the rabbit hole. but who doesn't like a good mystery