Rapidrob

A good friend of mine has a very nice,clean of rust 1986 BJ-40 with the 4 cylinder Diesel engine. He was replacing the air filter after an off road vacation and the air filter cover slid off and shorted out the 28 volt battery system. All circuits are dead.
His power cables are new and not burned. He has checked some fuses and found none blown.
I'm very good at anything electrical as I did it for a living.... and have volunteered to drive the 60 miles to his home and troubleshoot the problem. He is not DVM savvy or has any real troubleshooting skills.
I cannot find an electrical schematic for this vehicle that I can read. I found one that is a very poor copy of a poor copy.
I have owned FJ-40's over the years and know them well. This BJ-40 was imported from Belgium if that helps.
He tells me the "ignition" was NOT on when it happened.
What i need to know is:
Is there a fuseable link?
A main power relay?
High current limiter?
Known to fail in a bad dead short ,device or wiring that fails?
Any info would really help.
Thanks.

Rapidrob

I found one of the three fuseable links were burned as I expected to find. I still could use an electrical schematic if anyone here has a link to one that is readable.