Its actually a sensor switch, I had a similar problem and replaced it. The p/n was Delco 14036243. Search oil pressure sensor for some more info.

 

You should have a brown wire going to one terminal of the oil pressure switch. That wire goes to the choke heater fuse and will read 12 volts with the key on.

The other terminal of the switch has two wires on it. One wire goes to the choke heater and is usually light blue. The other wire is green and goes to the "bottom" terminal of the choke light.

Here's how that works:
The gauge fuse supplies 12 volts to the "top" terminal of the choke light. With no oil pressure the switch is open, so the terminal going to the choke is grounded through the choke heater. That puts 12 volts on the "top" light terminal and ground on the "bottom" light terminal and lights the choke light.

The Choke Heater fuse supplies 12 volts to the brown wire on the switch. When the switch closes (has oil pressure) 12 volts is applied to the choke heater. Now both the "top" and "bottom" terminals of the choke light have 12 volts, so the light goes out.

If your light flickers with the engine running you either have low oil pressure or a bad switch. Or you may just have a dirty or bad connection at the switch.

Your oil pressure gauge should tell you if the pressure is low or not. BTW, it has a tan wire going to it.

You can get a switch at AZ, Oreilly, etc. or on ebay.

The switch is installed just to the side of the distributor. The oil pressure sensor for the gauge is usually installed just above the oil filter, but sometimes people put it on a 'T' with the switch. Either place has the same effect.

Jack



Jack

 

I think the switch the OP is looking for is the one on top of the engine near the distributor.