I am living in an older house (1960's) and I am trying install a new single pole light switch (lutron maestro occupancy sensor switch). The old switch only has 2 screws, 2 black wires attached to the top, and 1 red wire attached to the bottom. How do I know which is the ground and where do the other 2 wires go?

Oh I guess italso has 1 white wire that has been capped

The ground has nothing to do with the other wires. In a house that old there may not even be a ground.

What you describe is a 3-way switch. Does the occ sens you got work on a 3-way switching setup?

The sensor does not work with a three way setup, that is a separate model. The funny thing is that there is no other light switch to turn on that light. There is a light switch on the other side of the wall that I have no idea what its function is however. I may have to look at some other light switches

Are the two black wires in the same screw terminal?

Yes the two black wires are screwed into the top of the old light switch. I checked another light switch and it is wired the same way. I also found a bare copper laying around as well.

And on the new switch, are there just two screws, or are there a few flexible wires coming out of the back of switch?

There are 3 wires, 2 black, one green with wire included wire caps (no screws). It also has one small silver wire for additional grounding.

With a motion type switch like than, you need to find the hot lead. I believe you will find "line" and "load" on the motion switch. Put the hot lead on the line and the light on the load. I installed one last week and it was so marked.

How do you find the hot lead in the house wiring. I am not familiar with which one it is in the house wiring. I can figure it ehere it is on the new switch as it is marked in the instructions

how do you find the hot lead in the house wiring. I am not familiar with which one it is in the house wiring. I can figure it ehere it is on the new switch as it is marked in the instructions .
You will need a neutral or ground wire to test it. With the wires disconnected, use a VOM set on AC 250. Touch one lead to a wire and the other to ground. 1 of them will show either 0 or 120 VAC. The hot lead is the one reading 120VAC. That goes to line.

Is a vom a volt meter? I don't have one of those. I don't think there is a ground wire and I am not sure what is the neutral as the wiring in the house has 2 black wires, 1 red, and a capped off white wire.

I'll bet one of the two wires that was under the same screw terminal is the feeder wire. If this is the case, these two wires, plus whichever wire from the switch is the "line" wire need to be connected together with a wire nut. The other wire will be connected to the "load" wire coming from the switch.

That's probably true. Maybe the red wire is the neutral wire?

No, what I was thinking was, since the two black wires were under the same screw, one could be the feeder and the other could be going onto another switch to feed something else. Any neutrals will be white.

By the way, how many fixtures does this switch control?

It controls one light and I guess that is what the capped off neutral wire is the white one. Maybe the red one is the hot live wire. I am not sure why there is 2 black ones then. I will have to post a picture tomorrow on and then link it here.

That's probably true. Maybe the red wire is the neutral wire?

My bet would be the black is the hot feed and the red goes to the light since the existing switch only controls one light. If red was hot, it would control 2 fixtures
White is neutral.