The Stovebolt Site Forums The Shop Area The Electrical Bay 57 chevy truck wiring

I was going to rewire under the dash of my 57 chevy truck as the dash lights and heater quit working. As i was inspecting things I noticed there is no voltage regulator on the firewall. The truck has had a small block engine and automatic transmission installed at some time. Is there a reason there wouldn't be a voltage regulator? I am debating rewiring the whole truck as who ever built truck didn't do very neat job. Thanks, Grady.

During the conversion they most likely upgraded to an alternator instead of a generator, which would not need a regulator.

Yes, it does have an alternator. Thanks.

If you our alternator has the 2 wire (red & black) jack plugging in to the side of the cast housing near the rear , that unit has an internal/ integrated regulator.

If that 2 wire lead plugs into the back of the housing there would need to be a separate regulator. In that case one of those wires would probably have a color other than black, like 1red, 1 blue.

You probably have an integrated regulator as stated in a previous post.

Here is an image of a current day replacement for an alternator with integrated/ internal regulator. The 2 wire (red $ black) connection is at 3 o’clock in the image. It would probably be at 1 - 2 o’clock when installed. The jack would insert perpendicular to the side of the housing. (Core). This is a 10si model. (si = systems integrated)

Here is an earlier 10DN alternator , external regulator, jack plugs into back of housing.

And yes - I learned all of this recently and the hard way, had to get bailed out by the helping hands here so Stovebolt.

I have the first picture. A black wire and a blue wire come out of the plug. Black wire goes to the battery connection along with red wire. Blue wire goes into cab. It was hooked to start switch. Not sure which post tho. I think solenoid post?

Correction on where blue wire goes. It is connected to the under dash harness

I see the blue wire is supposed to get hooked to voltage regulator on the under dash harness but my truck has the regulator removed. So question is where does the blue wire hook up to as the harness in truck has that blue wire coming out at the instrument cluster wires.

Your harness is different from mine, I must defer to higher authority.

Like Hebrew National.

Ok , I’ll bite–-
Kosher wiring? I don’t get it , obviously.

It is a fairly simple hookup. I am linking a YouTube video that explains it fully. In the beginning, it explains how to measure for the proper pully size, but it’s brief, so just watch the whole video. Very informative!

Here is a [Link].

OK. Watched video. Will see if mines wired like that. Thanks.

There was a real funny Hebrew National commercial a long time ago where Uncle Sam was holding a hot dog in a bun while a narrator described all the things the US Govt. allowed to be put in hot dogs.

With each item listed such as meat by-products, artificial coloring, non meat fillers, etc, the Hebrew National spokesman would say, "We Don't."

At the end he says, We're Kosher. We answer to a "Higher Authority" as Uncle Sam looked up and heavanly light shown down.

Well, the wiring in that video is definitely not kosher.

I see this all the time done like that, but it's not the way it should be.

1. The red 10 gauge wire goes to your starter/solenoid, not the battery.
2. The remote sensing wire (the short red one in that video) doesn't go to the alternator, but also to the starter/solenoid, or you never get a proper charging, because of voltage drop.
3. The exciter wire with the diode/idiot light goes to to the ignition switch.

Frank

Grady,
Do you have an ammeter? Do you want it to work?

Do you have an alternator light (aka idiot light)? Or do you want one?

The alternator wiring depends on the answers to these questions.

Otto - good analogy.

Mine has a black wire and a blue wire coming from the plug. Guess the blue wire is the white wire in the video.

Grady-
Your truck is 65 years old. It’s been modified, and you stated that you are not entirely pleased with the quality of the wiring done by someone before you. On top of all that , you have recently experienced electrical malfunctions.

It seems clear that an entire new harness is in order.

Have ammeter. Would like it to work. After 2 days trying to figure this out I'm beginning to think I should have just got a new complete harness like I did in my 49. That went pretty good and everything works great.

I second the motion.

Since you have an ammeter, the output wire from the post on the alternator (fat red wire in the video) runs to it, not to the battery. In the video, the white wire has an inline diode. If you have an alternator indicator light, you do not need the diode; the white wire simply runs to the light.

I don't know if there is an outstanding question. So I will cover what I think will enable Grady to get wired.

Do Not use wire colors for hook ups unless an entire new harness is being installed or truck has untouched original wiring.

USE THE FUNCTION TO WIRE THINGS. USE ANY COLOR YOU ARE PRESENTED WITH. USE ANY COLOR TO MAKE CONNECTIONS. MARK THEM WITH LABELS IF YOU WANT. DOES NOT MATER IF COLORS MATCH ANYTHING. IF THEY DO, GREAT.

Assuming 12V, indicator light (idiot light), solenoid starter with R terminal, ballast resistor, V8 style starter switch (momentary full CW solenoid position), ammeter that can handle the conversion and 10si alternator wired as "3 wire".

1. Ammeter needs a battery hot wire on one terminal and all the other "loads" go on the other ammeter terminal. Including the alternator.
2. Alternator wiring: 10si: Terminal 1 (R) wires to the idiot light, thru idiot light to ignition. Use an "ignition on" terminal that is not also used for the coil. ACC can be used. Terminal 2 (F) is wired to the alternator output stud. The alternator output stud is wired to the ammeter load terminal. The load side terminal of the ammeter is opposite where you wire a "direct" battery positive wire, whether from the battery post or from the solenoid battery stud. Mentioned in note 1. All of the other loads are wired to the load side. Ignition hot, headlight switch hot, etc.

A voltmeter is better to use than an ammeter.

...what brings me to my old question: how much can my old (41) ammeter handle wit a 60 amp alternator?

As we speak I'm going back and forth between "buy a 60 amp ammeter and try to get it somehow in the original cluster to keep the look"
and "just skip the old ammeter" (and maybe get a halfway decent period looking volt meter).

Actually I'm not exactly excited by both solutions.
An alternative would be a shunt with two diodes, so I can keep the original ammeter working.

Frank

There is a shunt across the terminals that provides a path across the meter.

Ed

I'm curious if anyone here has ever damaged their ammeter by using an alternator. It seems to me that if high current will cause damage it would come from the battery not the alternator. The battery can output several hundred amps while the alternator has a definite max at high rpm. Maybe this is a solution looking for a problem? As I see it the only time the alternator will push even close to its max amps through the ammeter is when the battery is totally discharged.

Mark

I agree with Mark. The "high current" is only there when the truck's electrical system demands it. Assuming "normal" lighting, ignition system, heater fan and radio, you will never approach 60 amps from that alternator except for charging a mostly dead battery.

Those "normal" systems actually reduce the alternator charging current available to pass through the ammeter.

Mark

The ammeter is reading current. Both ways. If a load draws current, it pulls the needle to minus. The alternator is wired to the ammeter so it can be read by the meter, and can get to the battery to charge the battery. As the alternator regulator adjusts alternator output to keep the battery charged, the needle will pull towards positive. Hopefully as you run down the road you will see the needle a tic on the plus side. The alternator will only put out what is needed. Probably never see it's full output used on a low accessory old truck.

As for capacity of your ammeter: The meter has two flow paths in parallel. The meter "wire" and the big shunt "wire/copper/brass buss bar". Almost all of the current runs thru the shunt, which is a bypass. Milliamps go thru the meter movement. Can't say who's ammeter will be sufficient for who's truck. It's a no brainer to go with a voltmeter. Many times you can get one the size you need and apply a face decal to match the "look". When key is off....A ammeter needle rests in the middle. A voltmeter needle rest at CCW.

1. Professionals, automotive electrical companies and Gauge manufacturing companies recommend a Voltmeter.
2. A voltmeter actually warns better and gives more info.
3. Most of the harness vendor's kits do not support ammeters.
4. The auto makers went to Voltmeters or indicators a long time ago.
5. The wiring is one 12V power source and one ground. Supplement it with an indicator.
6. No one has said an alternator will damage an ammeter.
If a persons "conversion" is to 12V. The amp draws should be 1/2. This would be less current thru the original ammeter. At the same time, if their conversion includes add-ons that draw more amps, it may cause a problem. Powerful headlights, sound systems, heaters, high watt devices. I have not researched if the milliamp meter movement is protected/limited no matter the overall amp draw and whether the shunt is robust enough to handle any draw that a person could add to their truck. This is the caveat I mentioned in my assumption paragraph in previous post. I'm guessing no problem. You could fuse it.

I agree. That's my point. Likely because an alternator will not damage the ammeter but I am curious if someone has experienced that situation. Yet we continue to have people genuinely concerned about whether or not their ammeter can 'handle' a 60 amp alternator when in fact it would be a rare instance that the ammeter sees anywhere close to the alternator max output. And yes by all means fuse it or install a fusible link in the battery charge wire at the starter solenoid to protect the harness including the ammeter.

Mark

Dodge was quite "famous" for melting amp gauges, after they got a 70 amp alternator and AC, cause the shunt was attached to the ammeter and generated a ton of heat under the dash, while Ford and GM used a remote shunt in the engine bay for that reason.

After a lot of reading and soul searching I came to the conclusion, that if you have an additional 10 or 8 gauge wire going from the alternator to your starter as a charging cable, it should provide enough of a shunt to protect your ammeter - at least with the typical load like lights/ignition/heater/radio etc. and probably also charging an almost empty battery.

Frank