80 vette... Anyone know when the low fuel light will go on?  does it come on before starting the engine?  I am trying to find a way to test it before running out of gas!! 

It comes on with under 3 gallons in the tank, if it actually works. Does not "test" when you start the car. You can get a peek at the little circuit board to see if it's there by removing the glove box insert.

Yep it is there because I just bought one and did not know how it is supposed to act.  So now I need to drive it around to empty the tank!!

Mike, do it just come on at once, or does it come on dim at first, then get brighter the closer to empty it gets?
I know it comes on like you say, about 2-3 gallons, but don't remember if it works like the other GM cars, where it comes on dimly at first, then gets brighter and stays on bright at about 2 gal.
Just curious...

I've never noticed the low fuel lights as being dim then brighter. Now that I have all 4 of mine working, they're pretty much always on! That's cause I keep the tanks low so that I can have fresh gas all the time. I'll siphon a tank and put the gas in my work van and add fresh.

One of my little circuit boards was missing, which is a mystery because I've had the black 79 for 23 years now. I assume when the dealer swapped out the 8track for a cassette radio when new it got left off. The white 79 had a defect in the printed circuit that I bridged with a piece of wire and solder.

I did test the repairs by siphoning the tank with the car running til the light went on. Pretty much emptied the tank and then added the gas back in til the light went out again.

Just at E  and no light.. i know the bulb is good.. i just wish there was a easy way to test it.. i guess i will keep a gas can with me...

Or do as Mike did, and siphon the fuel out to see if the lite comes on...better than finding out the hard way!

Or you could have one like mine.  The light stays on all the time.  Ever since I changed out to the new wiring board behind the gauge pack.  Before it never came on, now it never come on 'cause I took the damned bulb out!

[QUOTE=dnv]Or you could have one like mine.  The light stays on all the time.  Ever since I changed out to the new wiring board behind the gauge pack.  Before it never came on, now it never come on 'cause I took the damned bulb out! [/QUOTE] Is the little circuit board installed? I've heard of others missing it, just like my black 79 was missing.

Yup I tried the siphon thing but didn't take enuff out - although I thought I had. So I ran the tank down, and sure enuff when the needle is pretty much on E it starts to come on - well depending on slope the car is on it may be on or go off (initally) but doesn't take long to turn hard on. That's when I know it's time to extend the mortgage again...