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Hello,
I have 1969 C10 fleetside/shortbed. I have just installed a new 350 engine that came with a one wire alternator. How can I make my existing amp meter work with this configuration or is this possible?
Thank-you for any help.
Thanks,
Cliff

The purpose of the ampmeter is to measure the charging or discharging of the battery. The alternator, one wire or otherwise, is not an issue.

OK, but how do I wire the amp meter so the gauge works? That's my question.
Thanks,
Cliff

Slick,

I looked at a wiring diagram for a '69 rig and it shows a alternator with external regulator.

If this is correct, you would need to dump the regulator and stash the connector that went to it. It looks like the old alternator output through its BATT terminal into a RED #12 wire...this is the connection point for your new, single wire from your new alternator.

The DA plug that went on the old alternator can be taped up and hidden too.

If you don't want to connect to the old wire, you can run directly to the junction block that the old charge wire went to.

If this is all wrong, you can give me a big slap in the chops!

Stuart

I have this same question. Old amp gauge (1956), new one wire alternator. Someone please just state where each of the two terminals on the amp gauge hook to in general. One to batt hot and the other to alt output or what? Remember, don't want to read voltage or burn up old gauge. thanks

bartamos,

A '56 would have had a generator. The output of the generator went to the GEN terminal on the regulator, through the regulator and out to the battery on the BATT terminal.

If you had a generator, and now have a one wire alternator, hook the one wire from the alternator (BATT) to the wire that attached to the voltage regulator BATT terminal. Pull the regulator off, scrap the GEN and F wires and you should be all set. That BATT wire goes through your old ammeter and will read the output of your new alternator.

This 'should' work!

Stuart

Do the + and - terminals on the back of the gauge correspond to the + and - markings on the face of the gauge?

Jim,

My little drawings say that they do! The part that gets most folks confused is that the + goes to the battery and the - comes from the charging source and is also the connection for all the loads.

Stuart

Stuart,
Would the charging source then be the alternator?
When I turn on the ignition my meter swings to the + side.
I'm not sure that the alternator is charging my battery.

Jim,

Yes, alternator or generator. The system can't generate a charge more than battery voltage by merely turning on the key so it wouldn't seem possible that the needle would swing to + by doing this. If the wires on the back were reversed I could see this happening, but the deflection should be quite minor.

Stuart

That's why I asked about the terminals on the back.
It seems that my amp meter is reading backwards. If I just turn on the lights the meter also swings to the + side.
I'm certain I have only the battery and horn connected to the terminal behind the + mark on the gauge.
Everything else including the alternator is connected to the terminal behind the - mark on the gauge.
When I run the engine the needle on the meter is in the - part of the gauge markings.

Jim,

Everything works right...just backwards. Your profile doesn't' mention what kind of rig you have. Would a GMC with reverse polarity read backwards or would its gauge be marked differently.

I don't know if my info is 100% accurate, but I think it is. If you solve this problem, let me know the results, I might have to update my little picture.

Stuart

Stuart,

I'll update my profile. It's a 53 Chevy 3100, positive ground.
It has the chevy gauge cluster. I have another gauge cluster and I'll do some testing with it. I may have to reverse the connections on the back to make it work right, regardless of the + and - markings on the front of the gauge.

Jim,

I hope your post indicating "positive ground" was a typo!

Stuart

It wasa typo. I'm positive that it's a negative ground.

atomarc. thank you for your reply. I am a liitle unsure yet. Please consider all old wiring was stripped out, a new 1974 454 engine installed and all rewired with American Autowire. They don't seem to address an amp meter/gauge just a Volt meter/gauge. So I'm sitting here with a new 100 amp One wire alt and a old amp meter. How to wire from scratch? Do not have a reg or any old features/wiring on the truck to go by. Plus (+) to ignition battery source and neg (-) to somewhere on alt?

bartamos,

The single wire from your alternator would go to the - side of the ammeter along with all the loads...with the exception of the horn, but including the keyswitch.

The + side would feed the battery, and the horn. This is the basic wiring as I see it.

Many folks think having a meter in the dash that has the ability to pass lots of current is a hazard. A voltmeter works fine to monitor the battery and charging system and doesn't pass current. This is probably why your harness manufacturer supplied wires for a voltmeter and not a ammeter.

The alternator makes the 'juice' which goes through the ammeter on its way to the battery. Battery side is + and alternator side is -...simple as falling off a log!

Stuart

When I rewired my 56 last year using the American Autowire Highway Series, I was faced with the same issue. I called their tech support and was told NOT to use the ammeter. The reason they do not address the issue is that they felt the ammeter would become the weak link in the system, especially if you start adding modern electrical loads like stereos, and such. I switched to a voltmeter instead. You might want to call and talk with AA tech yourself before you try anything.

Thank-you Sturart for your reply. I haven't tried this yet but will be attempting it this evening after work. I will use a old amp meter as a Gunia Pig so I don't fry my new gauge in the brand new gauge cluster I just purchased. I will be sure to let the forum know how it turns out so as to help anyone else in this situation.
Thanks again.
Cliff

Stuart, where did you get the wiring diagram?
Thanks,
Cliff

Cliff,

I found it online.

http://www.geocities.com/chevroletc1070/wiringdias.html


Stuart