i went to my 02 Yukon Denali and tore the dash apart and looked at the wiring..There were 2 different plugs i got one plug where my New Wire Harness hooks to..I just had no clue on what the other PLug is for...here is a pic of the Plugs..can someone explain to me what the Small Black/red Clip on is..and where or what it does...thanks..

 

this is what i think,
car makers make a wire harness for all of the yukon suburbans all of them so the wire system for example my dads truck has a plug under his seat for heated seats but he dous not have the option so mabey the extra plug you have is for a upgraded system witch was optional, or could be for onstar?

 

VW does the same thing as mentioned above. Was it plugged into anything or was it just there when u changed ur cd Player? As long as ur new cd player works with sound coming out of all the speakers then it's probably for some kind of optional thing like on star like mentioned above

 

it's the new style gm connectors (believe it came out in 99) cause they started itroducing bose systems cd changers etc and the old style gm connector didn't have enough pinouts to supports the extra crap they stuck in

it's awesome that car manufacturers leave extra harnesses and crap on their base models, didn't have cruise control on my van, but picked up a new column switch at the scrap for $50 and got the feature

 

it was plugged into the the back of the stock Stereo System along side of the main Harness..would it be for the 6 disc CD Changer that is in the separate Place..