Question on low fuel light 79SF

[TADracer]

Good morning everyone.

I am re-doing my front end and wish to install the low fuel indicator light that is in the gauge to another location since that gauge will not be used. Looking at the Clymer wiring diagram for the 79SF, I do not see how the light is powered. It shows a ground wire from the frame going to the sending unit and from the other side of the sending unit is a green wire up to the indicator light that has no intersections with any other wire for power. After the light the black wire goes right back to frame ground. Nowhere do I see power to operate the low fuel warning system.

Now I am thinking a keyed 12v up to the sender, then the green wire to the light and then the frame ground on the other side of the light. Would this be correct?

thanks

[xs11lover]

Boy you got me....could it be powered all the time with the same power as the background lights on the gauge and the sender just completes the ground? I never messed with it...

[skids]

I am pretty sure that the xs11 standards get the current from a transformer located inside the speedo housing. The voltage drops to something like 7 volts before it goes inside the fuel tank. I would be careful about this! 12 volts might be trouble for a special if it should be less. (not sure).

[TADracer]

I know. I have looked this diagram over a hundred times and just do not see it. I am installing an aftermarket gauge that does have a fuel gauge feature but since I do not have a standard with a sender, that feature is not available. It can act as the low fuel warning but I need to know how the sender gets power before I can hook anything up.

[TADracer]

That does make sense. I thought I saw 7v somewhere. Maybe in the test procedure in the Clymer manual.

[jetmechmarty]

Special? Without looking at a wiring diagram, I'd have to say that circuit is powered whenever the key is on. The thermistor acts as a switch to turn the light on.

[DiverRay]

The Neutral and Fuel lamps are both "hot", 12V. The switch on each of them works by connecting to frame ground. So when in neutral, switch completes circuit to ground and light is on. When you get low on fuel, switch completes circuit to ground and light goes on. All with 12V.(nominal) battery power.
Hope this helps. I can email a PDF of the diagram if you want it.
The 7V in Clymers is for the STANDARD ONLY, as it has a gauge.

[TADracer]

Hi Ray, I would like to see the diagram. I'll PM you with my e-mail