I hate you already! - LOL!
there is no visible relay and I don't believe there to be one
Correct like KidV says.
1) would I be hearing a click at all without a relay?
Like KidV says, yes the C.O.R..
The starter solenoid may also "thunk". However, it would be hard for you to hear/feel from driver seat, and even if it does, either:
1) Power to energize it may not be enough (because of power loses on the poorly designed starting system wiring) to overcome the return spring force, so it may not
completely actuate to close contacts, OR
2) It may completely actuate but you may have worn contacts so they may
not always close. (search "replacing solenoid contacts")
2) when I get the parts and go to replace the ignition cylinder/switch, beside the obvious need to pay attention to the way it was wired...
Not much to it, except inspect wiring for wear, corrosion, shorts, opens.
Jumps don't assist the problem...
Understandable, because this is not a battery charge issue.
... and tapping it does not seem to assist.
Tapping may help IF solenoid plunger moves somehow but barely closes the solenoid contacts. Tapping it gives it a
nudge to finally close contacts.
...The jumper wire from battery to starter is a safe temp fix, I did it for several months. Best to get a spade connector and fix it to the starter solenoid, then leave the other end hanging loose near the battery so you don't have to reach into the fender to start your truck.
Exactly. I describe the setup
here.
1) IF this consistently makes starter solenoid thunk, and crank the starter, then you know problem is upsteam- most likely fixable by adding the relay.
2) IF it makes the solenoid thunk but does not
consistently crank, it's probably your solenoid contacts. Easy to inspect/replace. 4Crawler has write-up on this on his site.
KidV says, $5 says your new ignition cylinder fixes the problem temporarily, but it'll be back.
Put a relay in.
Absolutely. Stock ignition switch may have pitted contacts from the poor design that had subjected it to 12 amps each time it started for the past 29 years. That's
just one of the straws that broke the camel's back.
There are other straws- the heaviest of which is the absence of properly-wired starter relay. After you replace the ignition switch, you'll still have a poorly-wired cranking system that still subjects ignition switch ST1 contacts to 12-amps. Choices:
1) Add a relay like KidV did,
2) Buy a hotshot kit
3) Buy 40-amp general purpose automotive relay and wire it in...
Either way the retrofit is simply wired this way:
Best of luck.