Wiring to Fuel Main/Aux panel switch on helm

[seasick]

I have to agree with Skunk in that the gauge should not be powered by the switch but by the ignition signal instead. In your plan, ho would you run the power to the gauge, tie pins 1 and three together and run that single lead to power the gauge? If you do then both leds on the switch will be lit all the time and you won't have a visual indication of which tank is selected

 

[MrD]

I have to agree with Skunk in that the gauge should not be powered by the switch but by the ignition signal instead. In your plan, ho would you run the power to the gauge, tie pins 1 and three together and run that single lead to power the gauge? If you do then both leds on the switch will be lit all the time and you won't have a visual indication of which tank is selected

Yes, I understand but I like this modification previous owner must have done, this way I can see fuel capacity without having ignition on or at refueling. When the switch is down the LED lights up in the down position, when UP the led lights the up position. Also just seeing or feeling the switch in the up or down position is enough for me to know which position it is in.
See pic here.

 

[seasick]

What pin were you planning to connect to the gauge power lead?
If you tie 1,2 and 3 together, both leds will always be lit.
Since there is probably only one wire for the gauge power you would have to splice the signals from 1 and 3 together and that will make both leds light up.

 

[SkunkBoat]

What pin were you planning to connect to the gauge power lead?
If you tie 1,2 and 3 together, both leds will always be lit.
Since there is probably only one wire for the gauge power you would have to splice the signals from 1 and 3 together and that will make both leds light up.

with 12V on 2 and the jumper from 1 to 3 and a wire to the gauge to power it from either 1 or 3 , both will light when the switch is in either ON position.
Not really a big problem. You can see the swtch and you only use it to check the tanks. The lit switch tells you there is power to the gauge.
If you don't want it lit, remove the ground off of pin 7.

 

[seasick]

If the 12v feed is connected to lug 2 along with the purple that powers the gauge ( nothing on 1 and 3),
the leds will show which switch position is selected and the gauge will be powered any time the aux feed of 12v to pin 2 is live.

 

[SkunkBoat]

If the 12v feed is connected to lug 2 along with the purple that powers the gauge ( nothing on 1 and 3),
the leds will show which switch position is selected and the gauge will be powered any time the aux feed of 12v to pin 2 is live.

then you are not switching the gauge On/Off you are using the Key. That works

wait a minute???

The purple wire is keyed 12V. you would not want to connect that to House +12v. It will always be on.

You can run house +12 to pin 2. No Jumper on 1 & 3. Run purple wire(keyed 12V) to gauge.(no connection to switch)
With key ON, gauge will display the chosen tank and not display if the switch is off (because there is no sender chosen)
The lights will show the chosen tank.

 

[seasick]

then you are not switching the gauge On/Off you are using the Key. That works

wait a minute???

The purple wire is keyed 12V. you would not want to connect that to House +12v. It will always be on.

You can run house +12 to pin 2. No Jumper on 1 & 3. Run purple wire(keyed 12V) to gauge.(no connection to switch)
With key ON, gauge will display the chosen tank and not display if the switch is off (because there is no sender chosen)
The lights will show the chosen tank.

Isnt that what I said?. The feed to the purple wire comes from the fact that it is a two wire connection to terminal 2 with the other wire being a 12v feed from somewhere.
The only thing the left side of the switch does is internally light the LEDs

 

[SkunkBoat]

Isnt that what I said?. The feed to the purple wire comes from the fact that it is a two wire connection to terminal 2 with the other wire being a 12v feed from somewhere.
The only thing the left side of the switch does is internally light the LEDs

no. the purple wire is key switched power. you don't want that on pin 2 with the house +12v

Purple wire goes directly to the gauge not pin 2 of the new switch.

 

[seasick]

When I said the feed comes from somewhere, I meant somewhere on the aux buss. That would be hot when the battery switches were on. I also said the purple wire was connected to pin 2 which also has the hot (aux power) feed. Once the battery switch is on, it stays hot. The only reason the OP needs to connect power to pin 2 at all is to makes the LEDs operational.

Am I missing something

 

[SkunkBoat]

I think we are talking past each other....again...

"the purple wire" is keyed 12V coming from the key switch. You agree?
You can use the purple wire to power the gauge when the key is on by connecting the purple wire to the gauge+ terminal. You agree?
The house 12v is on when the battery switch is on. You agree?

The switch is lit by 12v on pin 2. You agree?
There is no point in connecting the purple wire AND the house 12V to pin 2. Do you agree?

You can apply 12v house to pin 2 or run a wire from the gauge + terminal (the purple wire is on that) to pin 2.
But there is no reason to do both. You would have two sources of 12V power to the pin.
If you do that the gauge always has power whenever the battery switch is on, regardless of key position.

My point is you need to pick one 12v source. Either the purple wire or the House 12V

The OP wanted to power the gauge with the switch not the key.
To do that he would need to disconnect the purple wire entirely and use the house 12v on pin 2 and the jumper from 1 to 3 and a wire from there to the gauge+ terminal.
That would result in both LEDs lighting in either ON position and the gauge getting 12v in either ON position.

 

[seasick]

the purple wire" is keyed 12V coming from the key switch. You agree?
You can use the purple wire to power the gauge when the key is on by connecting the purple wire to the gauge+ terminal. You agree?
The house 12v is on when the battery switch is on. You agree?

The OP didn't want the 12v to come from the ignition, he said he wanted the gauge to work with the engine off. In that case, a connection to an AUX battery feed will do. Just about every switch on the switch panel has a daisy chained 12V 'switched' feed

The switch is lit by 12v on pin 2. You agree?
There is no point in connecting the purple wire AND the house 12V to pin 2. Do you agree?

That was not how I interpreted the operation of the switch but I am not sure since I could not find an actual electrical diagram of the switches internals. My assumption is that pin 2 gets connected to either 1 or 3 depending on switch position. I also assumed that there is only two positions and not a center position. Based on the picture, it seems that when the switch is in one of the two positions and there is 12 volts on pin 2. the p[in 1 or 3 will also have 12 volts but his application doesn't need it. I again assumed that pins 1 and 3 are internally wired to leds, one for up position and one for down position. Assuming that a ground is connected an LED will light. This was by sketchiest assumption since I had poor documentation and nowhere did I see a mention of back lighting.


You can apply 12v house to pin 2 or run a wire from the gauge + terminal (the purple wire is on that) to pin 2.
But there is no reason to do both. You would have two sources of 12V power to the pin.
If you do that the gauge always has power whenever the battery switch is on, regardless of key position.

My point is you need to pick one 12v source. Either the purple wire or the House 12V

Ha, this is where you and I saw the wiring differently. I assumed that the purple was a feed to the gauge and not the source of 12v.
I connected pin 2 to 12V and the purple to supply power to the gauge (remember that the gauge is analog and probably does not have a harness connection.


It looks like we are dealing with a different set of specs and definitions. Hence the different solutions

If I were doing the job, I would have used an ohm meter to verify the switching functions and I would have applied 12 volts and ground to the appropriate terminals to see what the lights did. I would have also used aligator jumber wires to verify gauge operation and sender operation.

 

[MrD]

Gentlemen, thank you all for your help. Works perfectly, tested yesterday. Btw, running power to the gauge from the toggle switch and not ignition. You are geniuses.