Gas gauge blues

[72 5500]

I sent out my gas gauge to be repaired and it still does not work. Just stays on empty. New wiring harness and a new sending unit. Power to the gauge and the sending unit is properly grounded. Any ideas????????????

[rideblue00]

Is there a ground at the tank? I dont know if there is supposed to be cuz my trucks apart.

[1963c-10]

make sure you have the correct color wires on the guage. looking at the rear of the guage from left to right should be brown / pink
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[72 5500]

Sending unit is grounded. Tested the sending unit with ohms meter and works properly. The wires on the back of the gauge are correct. I used a brand new wiring harness from Classic truck parts. By the way, the truck is a 61

[1963c-10]

Did you get the fuel guage sorted out?

[Rich 5150 69]

Have you tested the gauge, if and when you do use only 1.5 volts battery power or you will ruin gauge....if I remember this correctly, if I`m wrong somebody correct.

[luvbowties]

Originally Posted by 72 5500

Sending unit is grounded. Tested the sending unit with ohms meter and works properly. The wires on the back of the gauge are correct. I used a brand new wiring harness from Classic truck parts. By the way, the truck is a 61

Did you test gauge-movement, with sending unit removed from tank, and moving float, by hand, through its extreme positions? This should be done with a wire run directly from send-unit to gauge--not using the 'factory' wire. Also, the 'power-input-terminal' should be from 'fuel-gauge' terminal at fusebox. *Check this terminal, with switch "ON", to ensure voltage is present and getting to gauge.* The "TANK" terminal should NOT be grounded directly, but only through the sending unit.
Sam

[Swed]

When i was driving My 62 from Atlanta to Pensacola FL I had to give the gauge a classic movie "knock knock" and the needle jumped up. Probably stuck some how. It did work for me during that drive anyway (I had to do it after each stop)
This don't actually solve the issue but hopefully a hint!
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[72 5500]

The needle moves freely and when the key is on the needle goes to empty. Pink wire has 12 volts when key is on, brown wire is conected to the sending unit. The ground wire on the sending unit is grounded. I pulled the sending unit out of the tank and moved the float to full and empty with out any movment of the needle.
I'm thinking I still have a bad gauge.

[luvbowties]

Originally Posted by 72 5500

The needle moves freely and when the key is on the needle goes to empty. Pink wire has 12 volts when key is on, brown wire is conected to the sending unit. The ground wire on the sending unit is grounded. I pulled the sending unit out of the tank and moved the float to full and empty with out any movment of the needle.
I'm thinking I still have a bad gauge.

You need to run this same test once more, EXCEPT with the tank-terminal wire disconnected from gauge AND from sender. Run ANOTHER, separate wire straight from sender-terminal to tank-terminal of gauge. What happens now when you manually move the float to FULL and to EMPTY?
Sam

[luvbowties]

Originally Posted by 72 5500

The needle moves freely and when the key is on the needle goes to empty. Pink wire has 12 volts when key is on, brown wire is conected to the sending unit. The ground wire on the sending unit is grounded. I pulled the sending unit out of the tank and moved the float to full and empty with out any movment of the needle.
I'm thinking I still have a bad gauge.

If your needle moves when you run a direct wire, as suggested above, your original wire is likely touching a ground somewhere, leaving your gauge seeing NO resistance, as in "B" below. This would cause gauge to read "E" all the time.
HTH,
Sam

[72 5500]

Before I sent the gauge out for repair, I bench tested the gauge and sending unit with a 12 volt battery. I wired it up as if it was in the truck and moved the float. No movment of the needle. With no power, the needle moves freely and when power is added, the needle goes to E. I did the same test yesterday with the same results.

I tested the sending unit with a OHMs meter and it is working correctly. 30 OHMs of resistence when float is in the full position and 0 OHMs when in the empty position. This makes me believe I still have a bad gauge.

[1963c-10]

could be a bad resistor on the guage even if was replaced
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[72 5500]

That is what I'm thinking, It was not replaced.

[72 5500]

Can anyone tell me what side of the gauge the pink wire is plugged into. On the Full side or the Empty side?

[luvbowties]

Originally Posted by 72 5500

Can anyone tell me what side of the gauge the pink wire is plugged into. On the Full side or the Empty side?

What color is the "other" wire? I'm guessing brown. If so, pink goes from fuse box to terminal closest to driver's door--Empty side; and brown from term. closest to pass. door, or Full side, to tank sender. **Please note: there just may be 2 brown wires in the dash area which should not be confused: one goes to fuel tank; the other goes to license plate light.**
Sam

The gauge-to-sender-wire can cause 2 problems. If it is "open", the needle stays on E all the time; if it is shorted along its route to sender at tank, it reads F all the time. Temporarily running a dedicated wire from gauge to sender(like straight from gauge, across back of seat, and to the sender) will eliminate EITHER problem. You then know what to do!

If problem persists after you have verified voltage to the + terminal, and run a dedicated wire, as described, to sender, then gauge is, as you apparently are already convinced, defective. In working on possibly 12-15 of these sixties-gauges over a number of years (from earliest in ~1975, to latest in ~2011), I've NEVER run across a bad gauge--just bad wiring, defective senders, and 'sinking' floats. In all these repairs, iirc I actually never bought a sender OR a float; all I recall were repairable, mainly curable via wire-repair or soldering. BUT I DON'T RECALL WORKING BEHIND AN EARLIER TRIAL-AND-ERROR EXPERIMENTER WHO COULD HAVE RUINED A GOOD GAUGE. Please do not think I am downgrading experimenters, as we all likely have learned untold info by doing so; but on electrical repairs, we can easily "smoke-test" a suspect component.

*You may learn a lot from reading this thread shown below. It shows problems, symptoms, and fixes--many which have been explained on here already, but which may lend credence to induce you to follow some new tips or ones already offered:>> http://www.stovebolt.com/ubbthreads/...84552&page=all <<.
Hang in there, keep us informed, and you 'and this forum' WILL get the problem turned into history!

[luvbowties]

Originally Posted by luvbowties

What color is the "other" wire? I'm guessing brown. If so, pink goes from fuse box to terminal closest to driver's door--Empty side; and brown from term. closest to pass. door, or Full side, to tank sender. **Please note: there just may be 2 brown wires in the dash area which should not be confused: one goes to fuel tank; the other goes to license plate light.**
Sam

The gauge-to-sender-wire can cause 2 problems. If it is "open", the needle stays on E all the time; if it is shorted along its route to sender at tank, it reads F all the time. Temporarily running a dedicated wire from gauge to sender(like straight from gauge, across back of seat, and to the sender) will eliminate EITHER problem. You then know what to do!

If problem persists after you have verified voltage to the + terminal, and run a dedicated wire, as described, to sender, then gauge is, as you apparently are already convinced, defective. In working on possibly 12-15 of these sixties-gauges over a number of years (from earliest in ~1975, to latest in ~2011), I've NEVER run across a bad gauge--just bad wiring, defective senders, and 'sinking' floats. In all these repairs, iirc I actually never bought a sender OR a float; all I recall were repairable, mainly curable via wire-repair or soldering. BUT I DON'T RECALL WORKING BEHIND AN EARLIER TRIAL-AND-ERROR EXPERIMENTER WHO COULD HAVE RUINED A GOOD GAUGE. Please do not think I am downgrading experimenters, as we all likely have learned untold info by doing so; but on electrical repairs, we can easily "smoke-test" a suspect component.

*You may learn a lot from reading this thread shown below. It shows problems, symptoms, and fixes--many which have been explained on here already, but which may lend credence to induce you to follow some new tips or ones already offered:>> http://www.stovebolt.com/ubbthreads/...84552&page=all <<.
Hang in there, keep us informed, and you 'and this forum' WILL get the problem turned into history!

CAUTION: SORRY: ERROR IN ABOVE: Should read, "...The gauge-to-sender-wire can cause 2 problems. If it is "open", the needle stays on F all the time; if it is shorted along its route to sender at tank, it reads E all the time. Temporarily running a dedicated wire from gauge to sender(like straight from gauge, across back of seat, and to the sender) will eliminate EITHER problem. You then know what to do!..."

SORRY FOR THE CONFUSION!
Sam

[72 5500]

I think I figured out my problem, I have a funny feeling the wires were backwards on the gauge. My pink wire is towards the center of the truck. I switched the wires and it still does not work. I'm thinking I must have damaged the gauge by having the wires crossed.

[61_FL_Apache]

Check the float in the tank. Mine had a hole in it and it sank to the bottom and stayed there.

[72 5500]

I have a working gas gauge!!!!!!!!!!!!!!!!!! Bad ground between the gauge and the mounting plate. I took the gas gauge out of a 64 Chevy panel truck and tested it and it worked. Cleaned off where the gauge grounds on the backing plate on the original gauge and it works.
Thanks to all for there input and suggestions. Have a great week end.

Tom

[LostMy65]

I'm currently trying to track down my fuel gauge issues.
I still have to try some of the suggestions in this thread, but I figured I should ask what might be wrong with the gauge if it reads full all time, even with ignition off.
The needle jumps ever so slightly when I turn on the ignition, but it always reads full even when the ignition is off.

[luvbowties]

Originally Posted by LostMy65

I'm currently trying to track down my fuel gauge issues.
I still have to try some of the suggestions in this thread, but I figured I should ask what might be wrong with the gauge if it reads full all time, even with ignition off.
The needle jumps ever so slightly when I turn on the ignition, but it always reads full even when the ignition is off.

Hey, LostMy65, a common cause is the wire running from the gauge to the sending unit at the tank. If it is "open"(not a good connection), the needle stays on F all the time. Temporarily remove this original wire and then run a quick/new wire from the gauge to the sender(like straight from the gauge, across back of seat, and to the sender). If the original wire was causing the problem, the gauge should now move off F and work. If it does, just carefully re-route and bury this tempo wire, making it the new, permanent one.