need help asap with factory wiring harness

[patgizz]

my 90 burb has the black/red stripe wire coming off the + battery cable with a factory terminated round end on it. i assume this configuration would be the same for any 87 pickup or 87-91 burb/blazer with factory TBI. i need to know where this wire goes. i don't have power to half most of the truck because i don't know where to attach that wire. i've been told it goes to the distribution block on the drivers side next to my brake booster by someone however this wire is not anywhere near long enough to make it there without stretching it out straight across the top of the motor. the only + terminal close enough is the alternator. could this be where it is supposed to go?