When replacing a light switch and fixture, I noticed there were only 2 wires...red/black connected to the switch. The new fixture has a black/white/ground. What is the proper way of connecting? The wires are the original red/black that went to the single pole switch. The fixture is a new light attaching to wall.
It sounds like whoever wired it used the red as the switch leg coming back from the switch. The black was used as the hot feed to the switch.
There should also be a black/white cable from the panel to the light fixture box.
One of the boxes has to have the hot feed from the panel in it. Your post only talks about the cable from the switch to the light.
Look again for the other cable in one of the boxes.