the rear lights should come on with the same switch for the front?
so if you turn the headlight switch to the 1st position so the instrument cluster is all backlit then the front side lights should come on and the rear lights too
if both rear lights are out, check to see if the brake lights are coming on too
if not then check the connections to the rear light clusters
yes the 'auto' position should work as this is the automatic setting that turns on the lights if its dark
also try the position 1 click further round with the small image of a light bulb as thats the manual postion for the sidelights