Kohler CV16S killer switch diagnosis

I am working on a Kohler CV16S (Craftsman lawn tractor) that would not spark.  I narrowed it down to the kill switch.  When I pulled the white wire off the ignition module and it sparks and the engine runs. The shop manual basically says that at this point check everything in the electrical system and see if you can find a problem. Can you help me narrow that down a bit and how to determine what the problem is?  The kill switch under the seat seems to work correctly. I think the brake switch is working, but not sure how to check it for sure.

The Craftsman tractor model is 917.271041.  The engine is a Kohler CV16S. Spec number 43514.
 
I appreciate any help you can offer. I've checked the fuel selenoid, the regulator, the seat kill switch, etc. and have not been able to pin point the problem.

Life happened and its been a week. Thanks for the diagram. I am trying to get back to working on this today. Some progress. The mower cranks when the seat is depressed and the brake/clutch is pressed. However, there is no fire to the plug. There is a white wire and a red wire that go from the engine coupling to the Spark Advance Module. When I detach the white wire, the engine starts and runs. Attached, there is no spark. So backing up, I know there is power on one white wire that goes to the brake/clutch switch. Not sure about the one that is coming back out. I need to check it with a voltmeter this morning. So, a couple questions.
1.  Should there be power (+7.9 volts) going all the way to the SAM on the white wire that I'm unhooking, or not?  Should that power be coming out of as well as into the brake/clutch safety switch when the brake is depressed?
 
2.  The regulator....one terminal has three white wires on it. Two go under the flywheel (not sure where they go to) and one goes into a connector along with the brown wire from the other terminal on the regulator. The other side of that terminal has two yellow wires that go back to the relays and switch. Not sure what I should find on those white wires.
 
3. Finally, I have taken the relays off an cleaned terminals, put them back on, but not sure how to diagnose them further. Any advise on that?
 
I think I'm close. Just can't figure out how to narrow it down further and hate to start replacing everything.