Low Fuel Light...Possible?
 

So I don't really trust my fuel gauge. I ran out once already when the gauge said I had 3/8 of a tank. As I was filling up this morning, I thought of a low fuel light when the tank only had 3 gallons left or so. I was thinking of using the tandem lock indicator on the dash for this light and changing the wording to "fuel reserve" or something. I have used low level sensors and such in fish tanks to signal water topoff, but obviously water isn't combustible...not sure about the sensor triggering a 12v source for the light. Any thoughts??

Re: Low Fuel Light...Possible?
 

Could you use a switch like this? https://www.amazon.com/Current-Sensi...a-660687002639

Re: Low Fuel Light...Possible?
 

I honestly don't know...Is a low fuel light triggered by ohms like a fuel gauge or a separate float that triggers the light.

Re: Low Fuel Light...Possible?
 

I was thinking the switch would trigger a light?

Re: Low Fuel Light...Possible?
 

Iirc, low fuel lights still read from the stock sender with a logic circuit to turn on the light.

Re: Low Fuel Light...Possible?
 

I have a low fuel sending unit it’s called a left turn comes on around a quarter of a tank 🤣

Re: Low Fuel Light...Possible?
 

Have ya' considered putting a slight bend in the sending unit arm to adjust where the fuel gauge is pointing to? Just need to know roughly how many miles you get on a full tank and then adjust when it's close to empty. I'm sure a very, very small bend would make a big difference, then repeat to fine tune things if you have to. If you choose this route, tracing the arm onto a piece of cardboard for future reference would help take some of the guess work out of adjusting if it's not quite right the first time.

Re: Low Fuel Light...Possible?
 

I am about to finish up some new wood bed...when I install it, I am going to try and come up with something or just keep filling up when the gauge reads just below half. I am not getting the best MPG either...and it isn't consistent. I have gotten 19.9 once (awesome) and below 10 once (UGH)...but usually hovers in the 11.5-14 range...usually towards the lower numbers. I just thought with a new crate engine and an EFI system, I should get around 15 minimum. Most of my drives are on a divided highway at 55-60 MPH at 8-10 miles...then a little city driving. Maybe I just need a better tune, but that is an entirely different thread....

Mostly was am brainstorming ideas to have a new light in the truck that is useful. :)

Re: Low Fuel Light...Possible?
 

OK, so I finally found a thread on a truck forum that shall not be named...and they have this same basic thread...and someone used this voltage comparator tapped into their sending unit wiring.

Basically it has 12v power & ground to the comparator and a light 12v and ground, then adjust the brass knob until the desired voltage level to turn the light on. For $5 I may try it.

Re: Low Fuel Light...Possible?
 

Cool, for $5 you can't loose.

Re: Low Fuel Light...Possible?
 

Looks too good to be true. Please keep us all posted

Re: Low Fuel Light...Possible?
 

This is basically what I did too. Just slightly bent the arm to get it close and actuated it with the switch in the "on" position to mimic the fuel level until I was comfortable with it.

Re: Low Fuel Light...Possible?
 

Also saw this metermatch It can trigger light for a low or high setting and adjust the fuel gauge readings...can also be used for temp, oil gauges, etc. but pricey.

Re: Low Fuel Light...Possible?
 

OK, so I just ordered a MeterMatch direct from the MFG for $65 shipped...hopefully it will solve my issues and give me the low level light I want. Will update after I install it.

Re: Low Fuel Light...Possible?
 

Any updates on this? I'm thinking of doing this as well

Re: Low Fuel Light...Possible?
 

Unfortunately not. I did buy the metermatch, but got caught up in life and now moving across country. I will get around to it, but I am not the fastest sometimes.

Re: Low Fuel Light...Possible?
 

Where are you moving to?

Re: Low Fuel Light...Possible?
 

Yeah, it's sound activated........the SLOSH.

Re: Low Fuel Light...Possible?
 

Well maybe not moving across the country, but moving up the east coast 1000 miles...to the Syracuse, NY area.

Re: Low Fuel Light...Possible?
 

You'll need to cut open the tank and add baffles to keep the fuel from sloshing, or else the light will be flashing on and off constantly.

Re: Low Fuel Light...Possible?
 

Ah, good call

Re: Low Fuel Light...Possible?
 

I don’t think it would be a problem until probably a quarter of a tank? That’s usually about where I fill up anyway. It will be interesting to see how it works.

Re: Low Fuel Light...Possible?
 

I wonder if it would be possible to use one of these? https://www.camarocentral.com/1968_1..._p/con-29a.htm

Re: Low Fuel Light...Possible?
 

The simplest hookup would be +12v and ground to the left blue block (#1 and 2). Then tap into the two wires going to your sender and connect to the white connector (#10 and 11).
Attach the full gauge voltage to 10 and the sender return to 11.
If you are almost empty, the wire on 11 will be much lower voltage. Adjust the screw (9) to internally reduce the reference voltage on #10 until the relay trips, sending +12v power to the light from relay #5. Done. If the tank has more fuel (and more sender voltage), the light is off.
https://www.ebay.com/itm/40120428441...IAAOSwPzhZ8p1A

Re: Low Fuel Light...Possible?
 

Master Chief,
Thanks for posting that info. Besides my 64 C-10 I also own a 62 Pontiac. Many years ago I bought a Speedometer cluster with the Speed Alert & Low Fuel light option for my Catalina. It didn't come with electronics to make the Low Fuel light come on. Once I get my truck finished then it's on to my Pontiac to get it done.