TBI Wire Harness Help

[OffroadZ71]

Hey guys , im gonna ask my question on here because no one is really responding on the other forum which i posted this same basic question..

I have started cleaning up the wiring in the engine bay and everything is going pretty good so far. The only problem i have ran into is this one wire, which is place so crappily by gm. it is the only wire that literally runs down the middle of the firewall down towards the brake booster. Its green in color and it has a strange grey clip mechanism on it and it is connected. Im thinking it may be for the a/c, going be diagrams.

I had my tester out earlier and found it had no power with key on or off, no power when in reverse and no power when its running. The schematics i found only really shown two solid green wires. One being for the fuel injector, about 99% sure its not that, and one for the a/c compressor. Cant go out and test because thunderstorms just started coming through

*This is on a Factory 1990 5.7 Tbi harness*