Gas Gauge Connections

[umfangler]

I am trying to hookup a gas guage and need to know the connections. It has 4 screw terminals on it. One is marked G which I assume is Ground. One is marked L that goes to the Light. The other 2 are what I need to know about. One is marked I and the other is marked S. -Brian-

 

[Silvertip]

Re: Gas Gauge Connections

the "I" terminal is ignition. That terminal must receive +12V when the ignition key is turned on. The terminal marked "S" connects to the fuel gauge sender terminal at the fuel tank.

 

[boatgrunt]

Re: Gas Gauge Connections

You are correct on the G and L. The "S" is for "Sender" and should be the wire from your gas tank sending unit. The "I" is for ignition and provides power to the gauge. The I is usually run from the ignition switch to the "I" post. I would hop a small wire from the I to the L. <br /><br />Make sure to use tinned wire, heat-shrink tubing or sodder and to secure the wires when installing gauges. Good luck!

 

[Silvertip]

Re: Gas Gauge Connections

No! - Running the I wire to the L terminal means the gauge will work only with lights on. Run the I wire to the ignition switch (or a wire that has 12 volts on it when the ignition is on.)

 

[Boatin Bob]

Re: Gas Gauge Connections

I think what boatgrunt meant was that the light would be on whenever the ignition is on not that the gauge would only work when the lights were on.

 

[boatgrunt]

Re: Gas Gauge Connections

Boatin Bob - thanks for clarifying. I'm not sure what Upinsmoke was saying, but on my boats, I have not wired the gauge lights to a dashboard switch (if that's what he thought I meant) but straight to the ignition. When the key is turned on, the gauges and gauge lights turn on. Sorry if I wasn't clear.

 

[Silvertip]

Re: Gas Gauge Connections

That's exactly why I questioned the statement. A separate light switch is normally used for anchor and nav light wiring and instrument lights are normally fed from that switch. The Nav/Anchor light function can't be provided by the ignition switch - it can only provide switched 12V to that system.

 

[boatgrunt]

Re: Gas Gauge Connections

thanks Upinsmoke - so not to confuse umfangler, let me see if I can summarize:<br /><br />On a gauge, the L post must be wired to receive power and subsequenty to light the gauge. To do this, you can wire the L post in conjunction with a dashboard switch, thus allowing you to turn the gauge lights on only when you need them. You can also hop a wire from the I post to the L post. This configuration will cause your gauge lights to always be on when the ignition key is turned on. The amount of voltage used by the gauge lights is usually not enough to make "constant lighting" ever a problem.

 

[Silvertip]

Re: Gas Gauge Connections

Agreed -- but not typically the way boats are wired these days. The theory is that if you need dash lights, you also need the NAV and/or ANCHOR lights on so they are wired to that switch.