[T2] Helping Newby with 77 weekender

[steve blackham]

I was cruising around my neighborhood this evening on my new (1974) Suzuki TC125 when I noticed a bunch of neighbors hunched down, looking into a BayWindow engine hatch.  Like a moth to a flame, I couldn't help myself.  I had to stick my nose there also.
The guy just bought this bus from a guy in Washington on EBay ($10K) ouch! They shipped it down and it didn't run.  Ouch!One neighbor was screwing around inside the dizzy.  Said it had spark but wouldn't run.
I told them I have been working on Buses for over 40 years (bad mistake) and I would run home and get a volt meter, dwell meter and timing light.
With the volt meter I found 12+ at the coil and got the points to spark, but with the engine cranking got no dwell signal.
Popped in a known good coil.  Still no dwell signal.  Ran a jumper over to the battery and it started right up, for a second anyway.  Disconnected the jumper and had the guy crank it while I checked the voltage at 15 on coil.
12 volts key on.  0 volts while cranking.  Ignition switch?
Looking at the wiring chart I don't see a different connection for circuit 15 from key on  to cranking.  Don't understand while that should make a difference.  While looking in the engine bay, I spotted something I don't have on my 77.  Wondering if it is a starter relay.  It is located about 6 " to the left of the battery on the top of the engine bay.  Multiple wires!  
I don't have the starter relay on my bus and don't really know how it works.  If this is indeed a starter assist relay could it be causing + power at coil key on  and no power to coil cranking?
Anyway it was after midnight, so I told the guy, I'd tow the bus up to my garage in the morning where I could compare its inners against my 77 and pop in my good spares.
Anyone had similar problems with an ignition switch or any guidance?
Much appreciated
SteveCenterlessville, Utah