Old switch replacement

[dans78]

This forum has helped me so much in the past, just wondering if I can get some advice or tips. I'm hoping someone can either explain which wires are which, or recommend a tool I can use to check and make sure I'm connecting the correct wire as the hot line. I've been studying the book I bought & have looked at the diagrams stickied in this forum, but want to check to be sure I'm doing it right.

Background~ My house was built in the early 1950's and these switches appear original.

I'm trying to replace a light switch that went bad, which controls a single light in the middle of the garage. There are two switches for this light (making this a '3-way switch'), one by the kitchen door (the one that went bad) and one by the garage door that is in box with another switch that controls an outside light. When I turn the breaker off it turns other things off, like the TV in Living room, so there are other things on the line.

I think I'll just replace both switches, but the problem I'm having is the switches are not marked for where the wires go like the new ones that are marked and also have color coded screws, at least that I can see. In fact, the switch in the double box has a ceramic backing and the terminal screws are in the top corners & the lower right corner where 2 black lines are joined & run toward the outside light switch. The book I bought at Lowe's details the 3-way and they indicate there should be black tape on the white wire if it's being used as the hot line (which I'm not sure if this is or not) and a red line that goes between the switches. Well the wires I'm dealing with are only black and white, no red, no white with tape or anything, the wiring is also pre-bare copper ground wire.

[HayZee518]

switches

I found two pictures of two different porcelain switches. One is a push button, the other is a three way toggle. Below them in the diagram shows a typical wiring for a light in the middle. Maybe you can relate to them when replacing your switches. any problems on your end write me back and I'll talk you through it.
Normally a hot goes to the common terminal. In your case it can be fed from either end. The load can also come off the common at either end.
My drawing shows the hot in one side and the load off the other. Easiest way to check for a hot is to buy a common neon tester with two probes. Now comes the scary part. Hold one prod with your thumb and finger and touch the other prod to the screws, one at a time. Look at the bulb in the tester. One side will glow slightly. Hopefully the wire connected to the common in one box will glow. This is your hot wire. one of the two travelers might glow - don't worry about this. that is normal. when you flip the switch, the common in the other box should glow and indicated the switch has swapped, energizing the load.

[dans78]

Excellent, thank you so much!! I'll try to get some time tonight or tomorrow after work to check this against my set up and let you know what I find!

[HayZee518]

from what I can deduce from your posting both the kitchen box and the garage box has two feeders. this complicates things but not for the switches. at the garage box the two gang - a hot and its neutral come in the box. the hot goes to a single pole device and the common of the three way. so you should have three wires under a wirenut. the neutrals are just spliced, two wires, one wirenut. the black return to the light fixture goes off the bottom of the single pole switch, the two travelers may be just a standard romex two wire [as you stated one black and white wires] normal wiring uses a three wire[white, black, red] anyway, at the kitchen box, there's another hot wire. and neutral. ok one cable goes in, another goes in and two come out. one set goes downstream of the box, one goes to the garage lights. one set is the return path from the remote switch by the garage door. its wires, black and white connect to the three way switch bottom two screws. another cable which goes to the garage light is also black and white. its black goes to the three way switch common. because all neutrals terminate at the same point in the panelbox, splicing the garage light neutral into the feeder neutral and downstream neutral will complete the circuit. the feeder and the downstream cables are spliced together black to black, all whites are together. see if this isn't what you have.

[HayZee518]

Your circuit

check out the diagram. it may be close to what you have.

[dans78]

HayZee518, I got it! Your diagram was right on! I just had to connect the black wires to the gold screws and the white wire to the silver screw and it was good to go! The wiring was wrapped in rough cover that I think was black with the brown paper material inside. Also the old switch by the garage door was almost just like the one in the bottom of the picture you posted. Thanks again!