51 Fuel gauge and electrical questions

[lelshaddai]

I have a couple of questions. I am working on this 51 Commander. I am working on the fuel gauge. I want to know if it is a bad gauge. There are 6volts going into the gauge when the key is on. There are no volts coming out through the sending wire. The sending wire is good. The sender is grounded to the tank and the body and is known to be a good ground. The sending unit has resistance after being checked with it attached to the tank and ground check. The gauge does not move at all when the key is on. Suggestions?


Second question. What are the electrical connections for on this part of the column by the steering box? I cannot find the parts in the book.
51 Commander, 232 Automatic drive.

[StudeRich]

What SHOULD the Fuel Gauge read? As in, HOW much Fuel is in there?

One Sure way to know what it should read, is remove the sender, ground it, put the Float at 1/2 and with the Key on "ACC" read the Gauge for 1/2.

The Shop Manual should show the Backup Light/Neutral Switch wiring under "Studebaker Automatic Drive".
And or in the Wiring Diagram.

[lelshaddai]

The sender is hooked up and grounded. I can move it and is shows resistance. The gauge needle does not move at all with the key on or when the sender is moved. It has power to the gauge.

[gjamesk]

Did you give it some time? I know the gauge in my 52 is slow to react by design.

[StudeRich]

It sounds like you have eliminated everything except the Dash Gauge, so you must need 526738.

[lelshaddai]

Here is a picture of the fuel gauge connections. 12v(green wire) to the reducer to the terminal. The sender wire is tan. Gauge cluster is grounded when installed. Are the two wires correct or do they need to be reversed? I am ordering a new sender. I do like the condition of the old one. Still shouldn't the gauge read when the sending wire is straight grounded?

[StudeRich]

here is a picture of the fuel gauge connections. 12v(green wire) to the reducer to the terminal. The sender wire is tan. Gauge cluster is grounded when installed. Are the two wires correct or do they need to be reversed? I don't know, the harness has been replaced and you can't count on wire Color.
Also i can't read the back of the gauge to see which term. Is marked Ign.

i am ordering a new sender. I do like the condition of the old one. Still shouldn't the gauge read when the sending wire is straight grounded? Yes it should if the dash unit was good, why order a sender when we already know the Gauge is bad?

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[lelshaddai]

I was looking up the resistance specs after I tested it and I do not know if it is correct. I had to set the meter at 2m to even get a reading. I saw an original sender on ebay and mine does not look like it. It made me wonder. That is why I ask if you can ground the sending wire to force the circuit closed and it would make the gauge work, if it works. I am pretty sure that that connections are correct. I just wanted to make sure.

[gordr]

I would say your gauge is toast. Inside the gauge there are a number of resistors, actually tiny heating elements wrapped around bimetal strips that bend when heated up. With all external wires disconnected, both studs should show continuity to ground on the order of 20 to a few hundred ohms. Exact numbers unknown to me. Zero, or near zero is a short, and means a faulty gauge. Likewise, infinity on either stud is an open, and means a faulty gauge. There should also be some continuity between the studs, within the same range.

[Ron Strasser]

lelshaddai
I just checked a 12 volt gauge that came out of a Non Hawk Studebaker. One terminal to ground reads 429 ohms and the other 234. Between terminals the reading is 194 ohms.
If you power the gauge and disconnect the wire that goes to the gas gauge the gauge should read empty. If you ground the terminal on the gauge that the gas gauge is connected to, (while power is applied to the gauge) the gauge should read full.
I do not know the resistance of a 6 volt sending unit. I would expect that the resistance of the gauge would vary from close to 0 to about 150 or so ohms.
Another question; when was the last time the gas gauge worked?
Ron

[lelshaddai]

When I bought the car it had been converted to 12v(had a headliner fire previously) and had the reducers attached. The gauge has never worked since I purchased the car. The fuel gauge, Automatic Transmission hold switch and the horn honking while turning are the only electrical problems I have left. I have everything else working.

[lelshaddai]

OK, so I tested both posts to ground and to each other "0" ohms. Confirmed bad gauge. Start the process of finding one.