A potential cause could be the solenoid that powers up certain things only when the key is in the accessory position. Check your electrical bay for a small, beer can looking thing with copper posts sticking out on each side. (They look just like the starter solenoids used on cars when we were kids.) When someone else turns the key, it should click. Sometimes they fail intermittently, just due to age. Replacements are cheap. Just disconnect the power and unbolt.
You probably have several of these. Each one performs a different function, and if one is failing, I'd replace all of them.