I re-read your post. Looks like you've done much of what I've suggested already.
When you say "When I Conduct the same tests with the ignition in the on position I the tester lights on all connected fuses. When I test at the spade connectors the lamp only lights on the top and bottom connected fuses. The center position does not light at the connector - only at the fuse." what do you mean?:
1) On which side of the fuse is your test lamp lighting? (it should be BOTH sides of the fuse if the fuse is good)
2) Are you not getting power on the spade terminal post with the GREEN wires or the terminal with the WHITE wires on that 3rd fuse down from the top? (the green side is irrelevant to your starting issue. Only the white side matters)
3) Are you testing at the terminal POSTS on the fuse panel, or the spade CONNECTORS on the end of the wires?
You are correct that the brown wire feeding the top fuse should always be "hot" with 12v. The white wires on the two lower fuses should be "hot" with the ignition switch in both the "run" position and the "crank" position. If they do not have 12v in BOTH positions of the ignition switch, then the engine won't start.
If the SIIA is anything like the SIII, then I believe there is also an "accessory" terminal post on the key switch which ONLY supplies electricity in the "run" position and NOT the "crank" position. This terminal is used to supply accessories that you don't want to power while you're cranking, such as a radio. Make sure your white wire is not plugged into this unused extra terminal post on the ignition switch.
One last note...The fuse panel is a VERY simple device. A few bent strips of metal and a plastic holder for the strips of bent metal. There's not much to it that can fail. Presuming there's good metal-to-metal contact between the spade terminals and good contact between the fuses and their terminal clips, it's somewhat unlikely that the fuse panel is your culprit.
Last edited by SafeAirOne; 09-19-2018 at 06:37 AM.
--Mark
1973 SIII 109 RHD 2.5NA Diesel
0-54mph in just under 11.5 minutes
(9.7 minutes now that she's a 3-door).