Constant Voltage at Clock Fuse Y/N ?

[AnotherOldJeepGuy]

Got in the jeep this morning, no radio.  All black so is not powering up.  Before pulling the dash trim and radio unit I checked the fuses.  The Radio Fuse is good.  With the key off, voltage there is 0.  With key on it is ~12V.  It's worth noting that my ACC position has not worked for years since a shop replaced the ignition switch, which I didn't catch until long after the repair was done.  Anyway....

 

I also checked voltage at the Clock Fuse because even though I don't have a clock, I took a guess that since a clock would require constant power, that this clock fuse might also control the radio constant power.  Does it?. 

 

What I see is the voltage at the Clock Fuse is also 0 when the key is off, and ~12V with the key is on.  Is the voltage at this fuse supposed to be switched or constant?

 

I'll be pulling the radio unit Saturday morning (when it's not yet 100 degrees out there) so that I can probe the voltage where it really counts for powering up the radio, but I may ultimately be back at the questions above, so might as well ask them now.