OK, I desperately need someone's help! When we installed an identicalreplacement (used) 1.8 turbo engine (AEB) in our 1998 A4, we inadvertently didn't label the one "fat" black wire leading away from the alternator (taken from original motor)that has an "L-shaped" connector and it looks like it may be a ground. Anybody know if it is a ground, or if it is power? Where would it bolt on to? Could this be why my diagnostic connector isn't linking to my ProDiag and the radio isn't coming on?