Fuse 12 ACG (S)?

What does this fuse do? According to the underdash fusebox diagram it has something to do with the alternator, gauge assembly, electrical load detection, and something called PGM FI. This fuse is causing a low idle for me and check battery light that goes away when I remove it. What does ACG mean?
The car's a 92 civic hatch, d12b carburetor.

The car's a 92 civic hatch, d12b carburetor.

