Rewiring my boat and I have a Cole Hersee
I'm going out on a limb here and try to answer your question. I don't know what a Cole Hersee push pull switch is or what you are trying to do. However, I am familiar with automotove and marine wiring.
I would normally expect this switch to turn something on and off. The something in case probably expects a common ground which we can call negative. In a car, the common is the body. In a boat, you probably have to provide the common ground (plastic boat). When you turn the the switch on, you are providing power to it. So, you have a hot wire that goes to the switch we will call "line" and a switch leg we will call "load" The hot (line)comes from the power supply and the switch leg (load) goes to the something or two somethings. The negative is not involved in this switch.
You say this is a three way switch. This can mean several things. In this application, I believe you have a "something #1" and a "something #2" in which case you have one line and two load wires. For a better example, posiion #1 on your switch is OFF - while position #2 turns on the light in the cabin and position #3 turns on the light in the engine room. Or, it could be you have a Forward and a Reverse (either this (position) or that (position)). In that case, the power would most definitely go to the center tap. A different way to explain is is in Forward position, the head lights come on while in reverse, the backup lights come on. I know, I know, no head or tail lights. I'm just trying to esplain my thought a little better.
So, I have said all of that to say this. Using your volt/ohm meter, find out which terminal becomes live in position #2 and #3. I would try the first terminal as the HOT.
You can test this by applying power (12 volts) to the first terminal and then measure voltage in the other two positions to prove the theory.
If I missed the mark, please post a comment to this question and I will address your concerns.
I want to help you and learn at the same time.
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