The Stovebolt Site Forums The Parking Lot '60-'66 Trucks Amp Meter

Working on a 1965 C-10 that has gauges rather than lights. The amp gauge was never hooked up when the truck we rebuilt and a new wiring harness installed. Nor was temp gauge or oil pressure gauge.

I am trying to get all the gauges working to get rid of the under dash gauges.

I know on my 59 the amp gauge carried all the electrical load.

But seems to me the amp meter in 65 used a shunt.

Anyone able to explain simply enough to me how to get this gauge working? Or has anyone placed a volt meter in the instrument cluster?

Thanks

The 65 would have had a "Delcotron" first generation alternator with an external regulator. I seem to remember some sort of shunt circuit that comes off the regulator wiring that turns the "ammeter" into some sort of "charge/no charge" indicator. I'm headed out of town today on a road trip, but I'll try to see if I have a circuit diagram I can scan and email to you as soon as I get back. I believe I've got an old Motor manual stashed away that might have that circuit illustrated.
Jerry

Thanks, I should have included the bit that the owner has a one wire alternator now on it. He bought it that way and is trying to work with what he has.

I thought I found a diagram the other day, but have since lost it.

Since there's a non-original charging system involved, it's probably going to be necessary to design your own circuit. Look up the term "Wheatstone Bridge" and see if you think it would be possible to use the normal voltage drop from the alternator to the battery to provide a reference voltage to swing the ammeter needle from charge to discharge. It's been close to 50 years since I studied any kind of theoretical electronics like that, but it seems that would be the sort of circuit you'll need to use.
Jerry

Read all of this. http://www.shiftworks.com/flash/amp-gauge.swf Piece of cake.
M.A.D. likes to use big bulkhead mount terminal blocks. This is a good idea. It allows for less termination and is an excellent way to change from big wire to small wire. You probably have the printed circuit type gauge panel.
They have always had the opinion that a volt gauge is better than an ammeter.

I like a volt meter better, but it's not my truck. Does not have the printed circuit board. Individual gauges.

I have an ampmeter in my '62 C10 with the internally regulated alternator upgrade.

Hook one wire to the battery terminal on the starter. Hook the other end to the gauge. Hook another wire to the output terminal of the alternator. Hook the other end to the gauge.
Turn on the truck, but do not start it. The gauge should show discharge. If not, reverse the wires at the gauge.

Once that's straight, fire up the truck and run it up to about 1000rpm. The gauge should show a slight charge or nothing at all, depending on the condition of the battery.

It's an easy wiring update.

In 1962 the amp meter carried all the load since it had a generator originally. 1965 had a shunted system and the wires to the amp gauge are pretty small since the gauge only carries a small percentage of the load.

I'm just trying to make sure it will work without burning up the truck.

Thanks though.

Maybe this will help:
Convert to Gauges

Not sure I would trust some of that info.

The schematics will help. Shows me what was original.

Sorry, Roy- - - -the diagrams I've been able to find show the indicator light circuit, not the ammeter type. I know I've seem a factory original diagram for the ammeter, but I can't remember where- - - -possibly at one of the factory seminars I attended back when I was teaching electrical systems. There was a shunt involved that bled a small amount of current away from the main charge wire, as I recall.
Jerry

Thanks Jerry, the above link shows the gauges and I was able to print it off. I should be able to make this work now.

One link shows the two amp meter wires hooked to the same post on a connector, I can't see how that would work, but I do see how the original worked.

I should be able to mimic that. I'll put a couple of small fuses in each of the lines so I don't burn anything up if I'm wrong.

I had a 66 Pontiac Catalina one time caught fire when part of the charging system failed and the alternator overloaded the amp meter in the car.

Thanks to everyone's help and the diagram above I have all the factory gauges working now. More wiring to do to clean up a mess someone else made, but he now has his original gauges working and is pleased as punch.

Also installed a Vintage Air Conditioning system. Got it working as well.

Happy to hear your task turned into a success story.