Got a mission to fix up a rover. I used EVA construction mode to attach two batteries and four solar panel. The rover comes with a relay and a probe core. After it failed to move for unknown reason, I attach a command seat from another rover to it, still no dice.
The following screenshot shows there are power, the wheel is responsive, but for whatever reason, the wheel is not "spinning".
screenshot
I somehow managed to get it to move once by reattaching all four wheels in EVA mode, but it doesn't work in my second attempt.