# 1965 GTO Fuel Gauge problem



## stewartlong (May 30, 2015)

I have just finished restoring a 1965 GTO and have had the dash apart several times and the fuel gauge was working just fine until this last time I had to go into the dash and put it back together.

Right now the gauge needle is pinned all the way past "F" full. I do know the tank is full because it still has the winter full to the prime for storage in it. But I have had it out and ran it for about 75 miles.

What I have done to start a check on solving it:

1. Jacked the car up and went back to the new gas tank and sender and checked that the ground was good and secure and it was.
2. Took a test light and with the ignition on checked to see that I had power back to the tank on the fuel gauge wire and I did.
3. Went to the panel and just out of principle checked the gauge fuse and it was fine.

In trying to find current articles here on the Forum I'd like to get some fresh input before I pull the instrument panel out once again.

I think I know what the 2 prongs on the back of the gauge are for with 1 being for power coming up from the panel (which I believe is the left prong) and 1 that is going back to the tank sender which I checked (which I believe is the right prong).

The 2 nut and bolt combinations under the prongs I guess hold the face of the gauge on and the bottom one is a ground for the light. (I'm guessing here so please be easy on me).

Here's what I don't know about and need help.

This is after I checked with my test light that I've got power coming out of the new wiring harness from the panel to the fuel gauge.

1. Once I get to the back of the fuel gauge what is the amperage supposed to be and where on the back of the gauge do I find to measure it? What do I measure it with and amp meter?
2. Where is the sender that people are talking about and how it could be bad which I've read about? Is it sitting on the back of the gauge under that metal bar?
3. How do I check it and see if I need to replace it?

Again this gauge was working and now it isn't.

Any suggestions will be greatly appreciated.

Thanks.


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## cij911 (Oct 25, 2017)

Did you install a new sending unit ? The correct sending unit for a 65 is 0 to 90 ohms, so if you installed a 0 to 30 ohm sending unit, your car will show full until you are very very low.....

If you are not sure, measure the resistance of the sending unit by attaching one lead of your voltmeter to chasis ground and the other to the output of the sending unit (if you get anything above 30 ohms, then you likely have the right unit). If you get 30 ohms, you most likely have the wrong unit.

If you believe you have the wrong sending unit, remove the sending unit, and test the resistance with the float in the raised (full) position. You will likely find it to be 30 ohms if it in fact is the wrong sending unit.

Good luck


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## dcoydad (Sep 27, 2017)

My 68 had the same symptoms. Pretty ez fix with a new sending unit... Good luck.


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