3 post illuminated rocker

I am installing a 3 post Illuminated Rocker switch on a boat and the third post is confusing me. The switch controls a relay to turn on and off the trolling motor power. I can get the relay to function properly via the switch but can not figure out the configuration to also have the light in the rocker switch illuminate when switched on.

My set up is 2 12volt batteries run in a series.

Thanks in advance for any info.

Per the request of the system this post is regarding to a electric power prototype boat so I dont believe year make model will be relevant.

Are there any markings on the 3 terminals?  Are you switching power or ground?  Do you know if the lighted switch is an LED or a standard light bulb?

If switching power, apply ground to the 3rd terminal.  If it illuminates all the time, reverse the other 2 wires.

If switching ground, apply power to the 3rd terminal.  If it illuminates all the time, reverse the other 2 wires.

Yes, from left to right they are +, A, and a symbol that looks like half a plus sign pointing up and 2 small lines beneath it. I believe I am trying to switch power. The relay has 4 posts total. 2 small and 2 large. Here is a link to the switch. https://www.amazon.com/SPST-Automotive-Round-Rocker-Switch/dp/B001TQKKMC

thanks

The light is LED

Plus = 12 volts in.   A = Accessory or 12 volts out to your device.  That symbol with the 2 dashes at the end of the line is the universal symbol for Ground.  Notice that the end dash is shorter than the previous one, it is an arrow pointing down, to the ground.

awesome! Makes sense thank you. Seeing as I have almost no metal on board, would the negative terminal of the battery in the 24 volt series work well for the ground. I believe it would prefer not make guesses.

Ok, ran into a couple problems with this approach (because of my mistakes).

+ = 12 volts in from positive side of battery. Done

A = Accessory line to one of the 2 smaller posts on the relay. Done

Ground = Ground line run to negative terminal of the 24 volt battery. Done.

The other small post of the relay I have running directly to the positive terminal on the battery.

The 2 problems I am facing are:

1) light in switch is constantly on.

2) relay does not function.

I have the 2 big posts on the relay intersecting the main + line just after the circuit breaker.

Thank you

that did the trick. Thank you for your assistance!

I'm Back.

After figuring out the correct combination with your help, I ran all the wires in the boat and attempted to reconnect the circuits and am having the same issues. The challenge I have made for myself is the wires are now covered in protective armour covering, and although I labeled the wires at the connection end, I have something wrong and have blown 2 60 amp fuses. When I first connected power this last time a few minutes ago, the LED light in the rocker switch was on all the time.

So going on what you said, I applied ground to the 3rd post, and reversed the 2 other wires.

One question I have, is the 3rd post the one with the ground symbol? If I apply ground to the correct place on the switch, would there be anyway that reversing the other 2 would cause a short and blow the fuse?

Thanks for your help. Frustrated, but almost there...

The LED is connected to the ground terminal and also to the ACC terminal.  The plus terminal is supposed to be fed power.  When the switch is switched on, the power is now connected to the ACC terminal, thus lighting the LED.  If you apply power to the ACC terminal, the LED is always getting power, switching the switch to on, the device at the other end will switch on, but the light will not switch on and off because it always has power.

Ok, that makes sense thank you.

I have the ground connected to the ground terminal, leaving me 2 wires in the middle. One to power and one to ACC. I thought seeing as the light is always on, reversing the 2 other wires besides the ground would fix that issue. But instead it blew my fuse.

I am also running a basic voltage meter. It has a pos and a neg and a common. I hooked the pos to pos, neg to neg, then ran power to C terminal and it worked well.

I am wondering if I have both power lines running to the switch instead of just one. I do have a volt meter. I could check to see if both lines other than the ground are hot. If thats the case then I need to pull one off and connect it to the meter vs the switch. Learning as I go... Thanks for any input.

You had to have moved the wrong wires.  The only way it will blow a fuse is if you have power to plus and ground attached to ACC.  Or Vice Versa.