Since this question was raised, I decided to help my fellow hybrid enthusiast just this once and test this in my HiHy 4wd
. I know what you're thinking, but this is for science...
It most certainly did use both power sources and consumed a couple of bars on the battery pretty fast. I don't drive this car this way since I've become obsessed with MPGs, but wow. What a little beast.
I wonder if the other poster had less battery power than some threshold below which there would not be any assist???
Anyhow, have fun!