99 caravan electrical problems

My horn,headlights, interior lights, and probably anything else that should be accessible all the time only works if I turn on the ignition switch.
With the ignition switch in the on position all these things work. Is there some common part to all these areas ?
The brake lights and 4ways DO work without the ignition off.
Also which might be related to this problem, the radio and the clock in the radio stopped working. The radio just clicks for a moment in the speakers when you first turn the radio on.
Fuses and relays have been checked. Also I just put in a different headlight switch I got for $15 at the junk Yard.No change!!!!

Ooops, I didn't bother to check the fuses under the hood ! It ended up being the Memory IOD fuse.Why that has anything to do with the radio I'll never know. Hope I can help somebody else with this Post.