Anyone know how this works???

I have all the electrics hooked up in my savage now except for the lipos...
When i turn the wheels (HS7955TG servo is hooked up) i get lights on the BEC and RX... the RX light doesn't come on as easily as the BEC lights tho... I have a video of what's going on...

Sorry - it's a little shaky - the truck is hard to hold still while moving the wheels -lol-




I don't think it's a problem, I'm just curious as to how and why this happens? I've never noticed such a thing before =)