Here's one for those of you who are well clued up on optional extras:

My 80 has a lens for the low fuel light, and a working bulb, but the thing never lights up when driving. I know this, because

a) given the horrendous price of petrol in the UK, I'm always running on "E"
b) I once stoopidly managed to run out of juice a mile from the filling station
Under no circumstances has the light come on (not saying thats any excuse for running her dry, by the way!)

I'm given to believe (by some other vette websites) that the system works with an extra bit of printed circuit, thats fixed behind the cluster on top of the flexible circuitry - mine has this extra bit, but its obviously a home made part, that some one's made before i bought it.

Is it true that to get the light to work you need this extra ciruitry - was this a factory add on, or is it just a recognised way of getting round a broken system?

I may be wrong, but i thought the low fuel light was an option in the late seventies, but standard by 1980, so would GM not have incorported all the necessary circuitry into the fexible circuit sheet by then?

My flexible circuit sheet is pretty worn out where the multiplug goes in, and i was thinking of replacing it anyway, so perhaps this would get the low fuel light working again?
Any suggestions??

I've had my 78 for over ten years and early on...I wondered the same thing you are...does this light work? I finally mustered the courage to run on "E" and learned there are approximately 4-5 gallons in reserve once the needle nears "E" and at some point the light will go on.

It's not an option...it works! If you know the light is good, you may wish to "push" beyond the "E" is make it work. Calculate your mpg, for example 12 mpg around town and roll the dice. Of course, it could be a circuitry issue in which case, you'll need an electronics person to test the board. Probably, radio shack could do it...it's not difficult or time consuming simple requires one who knows how to test the circuitry.

Try this and keep me posted.

It does work!!!! I have one on my '79.

I have owned my Vette for 10 years and have only saw it come on 3 times...and believe me when it does come on..you are running on fumes!!

Happened to me a couple of months ago..I ''forgot'' to fill up after a Vette Event on a Saturday..didn't drive it on Sunday and the Monday mornin on the way to work the
RED light came on...I did make it to the gas station....total gallons..15.609.

I'm pretty sure the bulb is good - I've had the console out numerous times, and tested all the bulbs.
So there is actually supposed to be a seperate board in there? I've got the flexible circuit board (obviously!) that runs all the guages... plus a home made bit of rigid board, with a few resisitors and other bits of trickery, soldered into the back of the low fuel light, before i got the car. The original board must have failed. Could be dodgy soldering on the home made board, i guess.
Thinking about this, shouldn't the light come on as soon as you put the key in run - no matter how much fuel you have in the tank, the needle has to start from empty??
Actually, mine sometimes creeps up very slowly when the car's left. Are they supposed to read full-time, or only when the ignition is on?

Theo said: Thinking about this, shouldn't the light come on as soon as you put the key in run - no matter how much fuel you have in the tank, the needle has to start from empty?? Actually, mine sometimes creeps up very slowly when the car's left. Are they supposed to read full-time, or only when the ignition is on?

my gauge doesn't do drop to ''E'' when the ignition is off.

Sounds like maybe you have some problems with the circuit board.

Theo:

Soldering cracks, causing break in continuity...so I would definitely check that out.

My light works like this...and I've read reports that this is the way it should work. It first comes on when fuel in tank gets low but only glows for a brief period. Keep driving and it will come on after several more miles and will fade in until its at full glow...if I can describe it as such. So it's gradual not all at once.

Cool, so they're supposed to be full time gauges then.

Just wonder what's causing it to creep - probably the same thing as whats stopping the light working!

Anyone have a comprehensive circuit diagram of these things?

Regarding your question "does light come on with key in ignition and on first start" I don't recall off hand. I don't think it does but can't recall for sure. Seems like one of the lights don't come on at startup.

I'm on the road and won't get back til Friday, so can't check for you until then.

I've got a 79 circuit diagram but not sure if it breaks down the circuit board for the gauges...but I'll check.

hunt4cleanair said: Regarding your question "does light come on with key in ignition and on first start"

The only light that comes on is the GEN when turn the key to start the car and once the car is started it will go out.