So I did search on this but did not find in answer, so what the heck, thought I'd ask...

I am starting to use that 1973 1.7 car that I bought on Bring a Trailer and so far so good. My gas gauge is showing half a tank but the orange light next to the pointer remains illuminated. I'm assuming this is my low fuel warning light after checking the diagrams but would like to doublecheck.

Thanks for all of the help.

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yes low fuel warning, looking at that gauge, you might want to remove the float in the tank, take off the cylinder cover and clean the slider

Thanks George (and for the help yesterday).

The sender works, and the gauge will sweep through its motion as fuel is added / used.

Is there a separate circuit for the warning light?

The light might be right but the gauge or sender might be off. I got a multi gauge that showed a half tank but the light came on. Gassed up "just in case" and found out the gauge was wrong. you only have about an 1/8 of a tank when the light lites up.

Ah! Well that is a pretty darn important consideration. I better check how much fuel I actually have in the tank.

Thanks!

Just to close this out-I put fuel in the tank yesterday and you could hear her that the tank was basically empty, so you guys nailed it that I should trust the light over the needle indicator.

Thanks for the tip on what I can do to potentially address this George, you and the rest the people here have been just outstanding in the support you provide the community. Thank you

I don't trust either. When the tank gets to 1/2 empty I fill up. The sender is a linear resistor but the tank volume is not linear from top to bottom. The top of the tank is much larger than the bottom of the tank. Below 1/2 tank on the gauge the fuel level drops quicker.

As mentioned above, remove the sender from the tank, remove the cover and inspect. There are a couple of very thin wires which are the resistor that runs from the top to the bottom of the sender. These may need cleaned. The float needs to move effortlessly up and down on these wires. Be careful as the wires can be damaged very easily. A new sender is > $100 on Pelican.

The switch for the light is on the same float as the wiper for the gauge. The switch is just a piece of metal that bridges two contacts; when those contacts are connected, that provides the ground (I think!!) for the low-fuel light which then turns on.

That's about as simple as it gets. If the light goes on, you theoretically have about two gallons left; time to get fuel.

--DD

Again, thanks for the help Dave!

I figured out the needle was wrong but the light was accurate. 5 gallons in and the needle and light as both working now.

This car sat for 20 years, I think it just needs to be exercised.

Thanks!

But the lines are not equally spaced?