No power to fuse panel

I have some 1999 Freightliner (Century Class) electrical problems that got worse. I have no power to the fuse panel. I tried to start the engine (DD 60 series). It cranked a few times, but did not start; after that I lost all power to dash and to ignition key switch. I went to the battery box and checked the wires, connectors and fuses there. Everything seemed ok. Voltage was fine too ( 12.4V). I opened the cover to the fuse panel and noticed there is no power coming to the fuses. The voltage on the four wire lug posts reads 5.4V on the BATT lug, 0V on the ISO and the IGN lugs, 5.1V on the ACC lug. If I bring a 12 V wire and connect it to the BATT lug, would I be able to start the engine and drive the truck to a Freightliner repair shop ? I don't know how to rebuild the wiring under the fuse panel.

 

The batteries and their lugs are fine. So is the starter. I suspect that the problem is under the fuse panel. I had smoke come out of there sometime ago. Plus I have an issue with the windshield glue on there and sometimes some water gets in there. I need to figure it out how to access the wires underneath the fuse panel that come to it. Maybe there is a fuse there, burnt or loose wires, maybe a voltage cut off device, since I do have 5V coming on two wires. The SurePower device on the back of the passenger seat in the right side wall gets 5V and outputs 0.5V.