Our house was built in 1961 and I’m trying to change a light. I’ve replaced 10 or so already but this one has me stumped. There are 3 incoming sets of wires from 3 sides of the box. The whites are bundled together and 2 of the blacks are together. One black wire has a paint mark on it and was screwed to the light fixture. The fixture had a pull chain but worked off of a switch. There are also copper grounds from each side that continue across the box to one side together and disappear under the drywall. How do I wire this to a new fixture so the the old switch will work? Or should I change the switch too?
Since the light works by the switch your new fixture won't need a switch (pull chain). I like pigtailing if the wires are connected through the fixture not sure from your question. Basicly the 2 wires that connect to the existing fixture connect go to the new fixture. If a metal fixture there should be a ground wire that connects to the ground in the junction box, if a plastic fixture there may not be a ground wire on the new fixture. You should not need to change the switch.