Old alarm system component?
 

Does anyone know what this is for? There is an old Clifford System III Alarm system still installed. Wondering if it’s part of that? The big red wire goes directly to the battery. The bottom red wire is spliced the a red/green wire below the fuse panel.http://forums.pelicanparts.com/uploa...1743878205.jpg

You would have to trace out the wiring. Here is a link that might help you.
https://www.manualslib.com/manual/1007605/Clifford-System-Ii.html?page=5#manual

Looks like a circuit breaker that I had on my dealer installed AC.
Clifford would have used its own suppled fuse link for the battery connection.
You have any other aftermarket stereo, amp, etc equipment installed?
That Yellow wire normally goes to keyed ignition switch so it’s still has power or test those see if all are still active.