So this was a weird string of events .....
 

Puttering on my 1872. I replacing worn out parts , cleaning , etc. I just got the front axle back in, all new rod ends. I wanted to move the tractor ahead in the shop. I turned key, it started, ran about 5 sec. and stalled. OK, not a big deal. Oh snit , I cleaned the gas tank , and didn't refill. Well maybe there is enough fuel in the carb bowl to move it the 20 feet I need. Turn the key again - NOTHING , NOPE , NADA , Dead ! What tha ???

Check battery connections, turn key again, lights come on bright, oil light is good, NOTHING DEAD ! Maybe blew the fuse ? I grab the fuse holder cap, twist and pull, the whole fuse holder pull out. It shorts against the dash panel, sparky sparky , and shove it back in. I unhook the battery, disconnect fuse wires, remove, fuse IS blown (well now for sure). There was corrosion and green crud inside. A quick trip to parts store, new fuse holder, and fuses. I install the parts and try again NOTHING - DEAD! I dig out the Test Light, power here, power there, except no power when switch is in "start" position. Whats that all over the back of the ignition switch? Corrosion, green crud .... ARGGGGGGGGG !!!!!!! New switch ordered this morning. Come on Amazon !

YUP, that switch is TOAST.

I'd bet the contacts in the harness plug aren't in much better shape either.

Now inspect the switch plug I'll bet a dollar ta a donut that the wire ends in the plug are not in good shape and most holders are melted on the battery terminal
cavity.
you can get something like this:
Ebay #382231331196
Others here may have more suggestions.
Do check that yours is the same one you are purchasing :beerchug:

Edit: Finsruskw types faster than me.:biggrin2:

I thought of the plug being a problem. It actually looks good, no corrosion, just dirty. The corrosion seems to be within the switch itself and the contacts on the rear. I lucked out on missing out on a bunch of little burns, soldering 5 new ends on a new plug, dam it ! Switch is on order, due in next week.

Thanks Guys !

It seems every "new to me" Cadet needs a new switch. Bought a couple packs of the wire ends for the harness---somebody here posted a source (I can't remember now where I bought them, but the info is with my spare parts at the shop).

Is this the item you saved yourself getting burned on?

https://www.ebay.com/itm/Ignition-Wi...9F8:rk:12:pf:0

Yes , it is. All the contacts in that plug look good, not corroded , just dirty / grimy. Hit it with the brake clean , looks good . I will use my special nail file converted to spade cleaner and a spooge of dielectric grease upon reassembly.

May not be your problem, but that link for a harness plug is quite useful to me so thanks for the link!

These switches do seem to go bad and corrode. I have started filing them with the anti-oxidation grease used on large electrical connections. Happened to have some from a wiring project - it is very sticky stuff and I squeeze it into the switch through the keyhole. No idea it it helps, but was hoping it might prevent some water from migrating to the inside.

THE SAGA CONTINUES

Got the new key switch all installed , the contacts in the plug do look good .
set the battery in this morning , hooked all up..... turn key NOPE , NOTHING ,
DEAD , no lights .....what the ? ? ? ?

I actually still have the grill and hood off , shouldn't need the headlights
hooked up to run should I ?

Doesn't appear so looking at the wiring diagram.

The seat switch and the brake switch are both normally open correct , so if I
make jumper wires to eliminate them I should complete the circuit correct ?

Thanks !