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1956 Fuel Gauge Problems

Started by charstokes@gmail.com, March 28, 2023, 03:31:23 PM

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charstokes@gmail.com

My 1956 Cadillac Fuel Gauge Reads Empty With A Full Tank Of Fuel.

Replaced The Sending Unit, Still Nothing.

Grounded The Wire At The Sending Unit and Still Gauge Reads Empty!

Thanks For Input.

Charlene

Cadman-iac

Quote from: charstokesemail addresses not permitted on March 28, 2023, 03:31:23 PMMy 1956 Cadillac Fuel Gauge Reads Empty With A Full Tank Of Fuel.

Replaced The Sending Unit, Still Nothing.

Grounded The Wire At The Sending Unit and Still Gauge Reads Empty!

Thanks For Input.

Charlene

  Charlene,
 Check the wire at the sending unit for voltage. Disconnect it first for a proper reading. The sending unit is actually the variable ground for your gage.
 Remember to check the fuse before you go through the rest of this.
 If you don't get a voltage reading, check the continuity on the wire. It's a solid wire from gage to the sender. You might have a broken wire.
 If that checks out, then see if you are getting power to the gage. If so, I would suspect that your gage is bad.
 These can be repaired though, so don't toss it out yet.
 To do that the dash cluster will have to come out. It's very difficult if not impossible to remove the fuel gage with the cluster in the dash.
 Try this and see what you find, then let us know if you need more info.

 Rick
CLC# 32373
1956 Coupe Deville A/C car "Norma Jean"

J. Gomez

Quote from: charstokesemail addresses not permitted on March 28, 2023, 03:31:23 PMMy 1956 Cadillac Fuel Gauge Reads Empty With A Full Tank Of Fuel.

Replaced The Sending Unit, Still Nothing.

Grounded The Wire At The Sending Unit and Still Gauge Reads Empty!

Thanks For Input.

Charlene

Charlene,

If your gauge reads "E" with a new sender and/or placing a ground on the "brown" wire at the sender there could be several things;
a-   "Brown" wire is shorted to ground.
b-   There is no +12V on the "pink" wire at the gauge.
c-   The gauge is not properly grounded at the instrument cluster.
d-   Or bad gauge (as Rick stated above).

1-   Check the "pink" wire for +12V with the ign. key on.
2-   Remove the "brown" wire from the sender and gauge and check for ground (if there is a short ???) and for continuity (as Rick stated above).
3-   Check for ground around the gauge metal cover.

If all of these are good the gauge will need to be tested, the internal coils ground is a small strip which makes with the metal cover these tend to get corroded. You will need to remove the gauge from the metal cover to check and clean.

If any of the two coils are bad (burned out) the most predominant one to go bad would be going to the +12V "pink" wire, this one will get very hot if the fuel level gets down to ΒΌ or "E" for an extended time.

The resistance of these coils are about 125 ohms between the "pink" and ground (metal case), about 40 ohms between "brown" and metal case, and about 83 between "pink" and "brown".

Let's know what you find..!  ;)

Good luck
J. Gomez
CLC #23082