Where's my electrical gremlins? Wont start!

Sounds like you have an intermittent?

Once again here's the trick on the relay. In your photo, the two top terminals are what you need to check out. They are the magnetic coil of the relay.

Pull one wire loose. With a light or meter, see which wire is hot with the key in "start." Hook this wire back up. It can go to either of the two terminals.

Now you should have the other wire loose, and you should be able to follow it down and verify that it goes to the transmission.

Now take a clip lead and hook to the remaining push on relay terminal (the second of the top two) and the other end to ground.

THIS SHOULD cause the engine to crank in control of the key IN ANY GEAR

If not, you either have a bad connection in the start wire coming from the key (bad connection through bulkhead or at switch connector) or the switch itself is bad.

If it won't crank with the key, then next, move your test light inside and probe the switch connector. Still should be a yellow or yellow/ tracer wire.

I don't have a diagram for your rig, but now would be a great time to verify that the switch is RECEIVING good power, that is, no bad connections between battery and the switch.

So with the switch off and locked, find what wire at the switch connector is hot. Measure that carefully and compare to the battery. It should be very close. Next turn the key to "run" and turn on any loads you can, heater, etc, that are controlled by the IGN switch. Check that incoming voltage to the switch again for drop as compared to the key "off."