The Stovebolt Site Forums The Shop Area The Electrical Bay 1954 chevy truck ammeter

I have question about the wires going to me ammeter. Okay I know one wire goes from the ammeter to the voltage regulator and one wire goes from the ammeter to the starter, but here is my question: isn't there suppose to be a third wire that goes from the same side of the ammeter were the voltage regulator ties into, to the ignition switch ??

That seems correct, that side of ammeter should be labeled "-". Other pole "+" should have more than one wire as well. I didn't trace diagrams as you should find the correct one for your truck (which 54 I cant tell). Typical 2nd + wire is the horn fuse.

You can view/download/save a wiring diagram here:
http://chevy.oldcarmanualproject.com/electrical/wiring/index.htm

This might be for your truck:
http://chevy.oldcarmanualproject.com/electrical/wiring/pdf/54truck.pdf

Mikey

I will assume that the 2nd wire on the + side of the ammeter is how the battery will get its charge. Right now I have a wire from the battery on the ignition switch. I also have a coil wire and gas gauge wire on the same post on the ignition switch, I guess I am just a little confused.

If you don't know sparks well, you really need to follow the wiring diagrams. For me to tell you in words will be confusing and lead to errors.

My suggestion, download the correct diagram, go to FedEx Office, Staples, etc. print it out in 11x17. Use some colored pencils and trace the the wires. You might print several, one for Lights, one for Charging, etc.

Power from the voltage regulator needs go to the battery but for the ammeter to function it must pass through the ammeter. So charging power comes in the - and out the + then to the battery.

Looking at a 1954 wiring diagram on the - side should be a second wire going the the light switch AMM pole. This so when the lights are on and light draw will reduce the ammeter indication. The diagram also shows a tap or junction of the 2nd wire on the - to the ignition. You could place three wires on the - pole. So - side should connect to the B pole on the voltage regulator, the AMM on the light switch and the ignition switch.

The diagram + side wire to battery and another to the starter push button.

Mike

Here is a simple wiring diagram for the ammeter based on the 1954 GM wiring diagram and the FAM.
> Ammeter diagram

The wire from the gas gauge to the sending unit attaches to the terminal with the red tag in this pic.
> Gas gauge

- Lonnie

Don't be too quick to dismiss Mikes suggestion about colored pencils and tracing. We did that all the time in the Air Force tracing wiring diagrams for the entire C-130. Good idea and you learn a lot in the process!

Lonnie thanks for the diagram I was able to fix one problem, but I think I may have smoked my sending unit. I bought a after market gauge because my original took a crap. So when I was hooking it up I switched the wires on accident at first, it shows how much gas is in the tank but it wont go back down to "E" when you shut it off. Do you think that it is the sending unit or the gauge that I messed up?

If you disconnect the battery, will it drop to E? My bet is that you have it powered full time and not just when the switch is on.

No I have been disconnecting the battery when I'm not working on it. That is why I think there is something either wrong with the new gauge or the sending unit.

Glad the diagram helped.

Here is a good trouble shooting guide for your gas gauge:
> Fifth Avenue Tech Tip

If you have changed your 6v elec system to 12v and bought a 12v reproduction gas gauge, it will not necessarily return to Empty when the ign sw is turned off. The gas gauge sits at an angle in the gauge cluster. Gravity pulls the 12v needle down toward Full when the ign is off. The needle on an original 6v gauge should return to Empty when the ign is off. Don't know if that's true for reproduction 6v gauges.

- Lonnie

Hey Lonnie I looked at the Tech tip and according to it, I have a bad fuel gauge. When I ground the sending unit, the gauge is suppose to go to "E" but mine wont move. I take it that the gas gauge is grounded to the gauge cluster when you bolt it up?

Correction if I ground the sending unit and it goes to "E" I have a bad sending unit. If I ground it and it does nothing, the gauge is bad.

Yes the back of the gas gauge grounds to the gauge housing. Sand to bright metal a place on the inside of the gauge housing that the back of the gas gauge will touch. Also sand the "ears" of the housing where they contact the mounting bolts and nuts.

"DADS50" wrote some good posts regarding the gas gauge and sending unit. Also pics and video. I searched, but couldn't find them. Maybe he or another 'Bolter will provide the links to them.

- Lonnie

if you suspect your sender is bad you can remove it and test it with a meter

...click...
should read 30ohm full

Well I replaced the gauge again, I assumed it was broken. Classic parts gave me another for free. So I hooked it up and still doing the same thing. The gauge just always stays at the fuel level the tank is at no matter on or off, it wont go back to "E" when shut off. So I figured it must be the sending unit, so I replaced it also. Still the same thing. I made sure all the grounding points were sanded good and everything is wired up correct, the new gauge even tells you were to put the wires. I tested the ohm's on the old sending unit after the fact and of course there was nothing wrong with it. If I pull the sending unit wire off the sending unit, it jumps up to "F" like it should, I hook it back up and it goes back to the fuel tank level. All I can figure is these new gauges are not like the originals and that is just the way it is

I can't help but feel that the gauge has power with switch off as well as switch on.

Well before I broke the old gauge it worked like is was suppose to, no changes to the wires. As a matter of fact the battery is unhooked! It must be the non American made part is all I can think of

did you test it by having the sender out [with a ground wire to the tank/cab] and moving it by hand thru the whole range? if the gauge registers properly, then the fact that it stays at the last place it was when the power is off may be a result of it being a transistorized unit rather than the original coils, but the gauge is electrical, how can it move with the battery disconnected?

Bill

Is it possible your gauge needle is makeing contact with the gauge face etc., just enough to prevent it from 'coasting' back to empty with the key off?

red58 it dose not move with the battery disconnected, what I meant was even when the battery is disconnected it stays in place. The only time it moves is when the battery is hooked back up. I will try pulling the unit out of the tank to see if it moves through the whole range. Twotone I will check that but the fact that it will move back to "E" when you ground the sending unit post or that it will go past "F" when you disconnect the sending unit leads me to believe that probably not the case, thanks though.

There may not be anything wrong with the gauge. The manufacturer may have switched to a modern non-spring armature.

The old style movements had a tiny spring that pulled the pointer to empty, when power was added the magnetic field pulls against the spring and holds the pointer at tank level.

The newer movements (which have been used in cars since the 80's) do not have a spring. They work on a balanced magnetic field and have very low friction bearings. The armature moves when the magnetic field has a value + or - relative to where the pointer is currently at. When the power is off the pointer just stays where it is. You can see your tank level without turning the key on.

The new movements last longer and are less likely to stick.

Thanks for the reply I think that is the way these are made now.