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Is the fuel guage supposed to always be on, in other words always indicating fuel level, even when the ignition is off? I recently completed disassembly and restoration of the dash in my 70 Chevelle including replacing wiring, the flexible circuit board, etc... After reassembly everything works, but since the fuel gauge wasn't working when I got the car and now it is, I'm not sure if it's supposed to be on all the time or not. Also, if it isn't, where could I have gone wrong? The fuel gauge connects to the printed circuit board so I can't see how I could have wired it wrong. :confused: Finally, does having the fuel gauge on all the time cause an
appreciable draw on the battery? Thanks for your help.
 

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When power is removed from the fuel gauge the needle will stay where it was before power was removed.
 

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Originally posted by Steve S:
When power is removed from the fuel gauge the needle will stay where it was before power was removed.
Are you sure? My '71 SS with the idiot light cluster's gas gauge always goes to 3/4 full when the car is off, not matter how full the tank is. I think something is wrong with my sending unit or something though (bobbing needle a lot, etc).
 

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With the ignition switch off there should be no power to the positive side of the fuel gauge. The needle position is determined by a variable ground signal from the sending unit. With the power removed, the position of the needle will vary. I think mine goes down. After the car is started and power is sent to the gauge it will correct it’s self. Is it possible the harness wires are not correct? There is a B+ lead for the clock but it should be a separate orange wire.
 

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Discussion Starter #5
Thanks for the replies. My fuel gauge stays put when I turn the ignition off or on. The only time it changes position is as the gas level drops during driving and, of course, when I fillup. It also seems to be reasonably accurate when I check mileage. Last night I disconnected the battery to do some work and the needle didn't move even then. Bottom line, it seems to be functioning properly and accurately, it just doesn't drop back to "E" when the ignition is off like most newer vehicles do.
 

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There is an easy way to test for current draw if you are concerned that your battery may go dead. Disconnect the positive lead and hook the clamp of your test light the battery lead and the probe of the light to the battery post with every thing off the light should be off, if you have any current draw at all the light would be on. The amount of draw will determine the brightness of the light.
 

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My 68 gas gauge stays where it was when the car was turned off. Add or removing fuel with the key off does not have an effect. For instance, if I have 1/4 tank, and turn off the car, the gauge will still register 1/4 tank. If I then fill it up, it will register 1/4 tank until I turn the key back on, at which time it will show full. Removing the battery does not have an effect. It's as if there is friction in the gauge movement so that it requires energy to move the needle in any direction. I believe this is by design.
 

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I Have A 67 Chvellle That I Am Having Problems With The Fuel Gauge Also.so Far I Have Purchaced A New Chevelle Gauge And A Sending Unit Opg When I First Hooked It Up. It Seemed To Work Fine The Next Day When I Drove The Car The Gauge Was Reading Below Empty. So I Added 10 Gallons Of Gas But Still Reads Below Empty. Son I Ran New Wires To The Gauge Last Night .and It Seemed To Be Working Fine Until I Drove It Now It Is Doing The Same Thing.i Also Bought A After Market Gauge From Checker And Hooked It Up Now It Is Reading The Same Thing As The Other New Gauge.what Can I Be Doing Wrong
 

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67JOE6767 said:
I Have A 67 Chvellle That I Am Having Problems With The Fuel Gauge Also.so Far I Have Purchaced A New Chevelle Gauge And A Sending Unit Opg When I First Hooked It Up. It Seemed To Work Fine The Next Day When I Drove The Car The Gauge Was Reading Below Empty. So I Added 10 Gallons Of Gas But Still Reads Below Empty. Son I Ran New Wires To The Gauge Last Night .and It Seemed To Be Working Fine Until I Drove It Now It Is Doing The Same Thing.i Also Bought A After Market Gauge From Checker And Hooked It Up Now It Is Reading The Same Thing As The Other New Gauge.what Can I Be Doing Wrong
The sender wire is shorted to ground somewhere. With the sender wire grounded the gauge will peg at "E", with the sender wire open 9not connected to anything, gauge will peg to "F". Could be shorting to ground at the sending unit.
 
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