Packard Forum Index » Pre-War (1899-1942)

the fuel guage on my 34 quit working just recently and all the wires are connected, was wondering if it is connected thru a fuse and looking at the wiring schemtic I do not see where a fuse is or if it even has one. Does the sending unit in the tank go bad or the other possible idea is a short some where in the wiring any thoughts or ideas would be helpful.
If I check it out with a ohm meter what reading should it be, any tips or thoughts on this would be helpful. thanks

Does it read FULL or EMPTY all the time?

Check this out:
https://www.oldcarsweekly.com/restoration/fueled-frustration-fixing-faulty-fuel-gauges

The fuses (2) for all the protected wiring except the headlights is under the dash, more or less above the clutch pedal, part of the headlamp circuit breaker assembly. They are glass barreled and very large, easily inspected visually though better to use a meter.

The gas gauge can also show the crankcase oil level when you press the small button below the gauge to change the sender from the gas tank to the crankcase, if the oil level shows on the gas gauge when pressing that button, the dash unit is OK and the sending unit is faulty.

Most likely the cork float has failed in the sending unit, though occasionally the little bevel gear set fails from rust or corrosion. Of course other failure modes are possible, you'll probably have to drop the tank. The usual shops like Wolff Instruments can often repair the sender. If not, a while back Atwater Kent was making a reproduction. A bit of a chore to drop the tank, what with the filler neck inside the tail light casting, and the brass flex bellows in the line, very close quarters between the rear leaf spring and the side flange on the tank.

That is pretty neat. Never heard of a gauge that could read the oil level inside the car.

ptv, notice the word "Oil" below "Gasoline" on the gauge. And below the gauge is a button to switch the function. In the crankcase was a sending unit with a cork float. Not entirely an uncommon feature of better cars in that era. A couple of years earlier and you had neither the dash gauge nor a dipstick, just an underhood pointer on the crankcase.

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No idiot lights on that one..... I remember reading some cars had 2 taps on the side of the engine case. Opened the lower one, if no oil run out, you needed oil. opened the top one and added oil till it ran out and you was full.

The guage shows 0 all the time and the nob I press for the oil level also does not show when pressed.

I only see one glass type fuse under the steering colum with a larger rely about 1-1/2 wide and 3 inches long alumium covering. The only other lights that do not work are the brakes light that are supose to come on when the gear shifter is left in reverse.

Looking at the 34 wiring diagrams the gauge and senders do not go thru a fuse. Senders are grounded and either is selected by the switch. Sender output selected by the switch goes to one side of the fuel gauge. The other side of the fuel gauge appears to be supplied directly by the ign switch. Ign switch is supplied by voltage going thru the ammeter and ammeter is supplied directly by being connected to the battery terminal at the starter solenoid. The same terminal on the ammeter that supplies the ign switch also supplies voltage to the fuses.

If you have a voltmeter I would suggest seeing if there is any voltage at the fuel gauge when the ign switch is turned on. One terminal should have battery voltage or 6v and I would expect a bit less on the other because of the current going thru the sender. If both terminals read the same battery voltage I would wonder about the selector switch and if no volts then the fuel gauge appears to be the only thing supplied by a terminal on the ign switch so I would wonder about the switch or a connection.