Parasitic Draw

You're confused why the audio and memory fuse draws power when the van's off? I'm not sure if you're being serious or joking here...

The radio draws power when off to maintain the presets and other information for its memory as do other computer modules for certain functions, like locking/unlocking the doors with a key fob, or turning the parking lights on when headlight switch is operated. Vehicles with any sort of electronics have had parasites draws for decades...

Yes I know that the audio and memory draw power when the car is off -- but it shouldn't be drawing over 500mA. I simply was wondering why pulling both audio and memory caused the drain to drop to the same value of 50mA. I would have thought only one would be causing the excessive drain, which was the case when I remeasured later; only the memory was draining excessively. Not sure what happened the first time.

I was able to locate the excessive drain, it was coming from the instrument cluster, so all resolved now.

What was the drain and what was your solution?

The instrument cluster - had it repaired at an auto electric place. Put it back in, have acceptable draw now.