My 2004 Alphard has power slide doors on both sides. Offside works perfectly in all modes. Nearside works manually, when you use handle, dash button or remote to power open it gives long beep and doesn't move. Similarly if you try to close it. I've looked at all the obvious things (esp for nearside door) so its not a window open or the fuel filler cap open. I'm told the cable is OK. Does anyone have any suggestions on where I can find more information, what it might be, or who can fix it?