Intermittent power issues

[BlueHemi]

1979 C30 cab & chassis.
The 350 was replaced with a 454 before I bought it 4 years ago.
This issue popped up last night. I started the truck and let it run for about 5 minutes and shut it off. I turned the key on 10 minutes later to check the taillight bulb I replaced. All good.
I turned the key on 20 minutes later and...nothing. no lights, no heater, no click when trying to start. Zero power anywhere.
I pop the hood and hook up a battery charger, but it's showing a full battery. I turn the key on and can hear the blower motor for the heater, but nothing else. No lights, but when I turned the key to start, the blower motor stops and still no lights.
I cycled the ignition on and off several times, but nothing.
I took the battery charger off and waited about 30 minutes then tried to start. I heard a couch from the starter solenoid, but then nothing.
Any ideas on this would help out a lot.
I haven't done any electrical mods myself, but I have no idea what was done before I bought the truck.

 

[BlueHemi]

Addendum: while I was out running errands, my wife hopped in the truck about an hour ago and it started right up.

 

[Snoots]

Apparently, your truck doesn't care for you to drive it.

Check your ignition switch at the bottom of the steering column.

 

[BlueHemi]

Thanks Snoots, I'll give that a try.

 

[75gmck25]

Delete

 

[75gmck25]

I’ve explained this in a couple other threads, but here are the high points.

- electrical part of the ignition switch is at the bottom of the column, about where it goes through the dash. There are no electrical contacts up near the physical ignition switch.
- when you turn the keyed ignition switch there is a gear on the end. This gear moves a small pot metal “rack” , and the rack pushes/pulls a metal rod up and down the column. At the other end of that rod is the electrical switch.
- if the pot metal “rack” flexes or breaks/cracks, it does not move the rod accurately, and the electrical switch at the bottom of the column does not line up with the correct electrical contacts.
Bottom line - the ignition rack may be broken/cracked, or the electrical switch at the bottom of the column may need to be adjusted. A new GM ignition rack is very cheap, but requires quite a bit of column breakdown to replace.

 

[Old Guy Bill]

Myself, I'd start at the battery connections first...

 

[Ricko1966]

First thing check the battery connections at both ends,if you have the temporary bolt on ends take them apart and clean them. Again I'll detail a very simple volt drop. Take your meter check battery voltage remember it. Hook one lead from your meter and poke it on the negative battery post,not the terminal end,ground the other lead to the block no have someone try to start it. If the meter reads .5v or less your ground is good. To do the positive side you'd check from positive battery post to center of positive starter post. I,d check at the firewall junction first if it passes,less than. 5v there I'd assume you're good at the starter,if not check at the starter. Now say one of those test showed 6 volts and your battery tested at 13. Take 13-6=7 your cable or one of its connections is only passing 7 volts. If you are lucky enough that the heater blower,radio,lights,etc. Aren't coming on either,you don't need to use the starter to make the test. Just key on and all accessories on.