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The ammeter on my 1950 shows a discharge reading when driving. If I turn on the headlights at the same speed, the reading drops very slightly. When I am stopped at a red light, the needle does move into the middle. Is this a problem?

Driving 50 mph with no lights on



Driving 50 mph with lights on

Wires on the back connected wrong

I agree with Gene that is sure looks like the ammeter is connected backwards. Other than that your generator and regulator are working as expected.

A relevant piggy back. How in the world do you get photos to display so large? When I use the attachment manager everything I upload is tiny. A 1MB upload ends up a 50K image in my post.

Hi Tiny,

I think those are linked images from a hosted site. On my iPad if I hover over one of images I get a dialogue box that shows a linked url.

I agree that I like the larger image in a post. The real limitation is that if the hosting site ever goes away or restricts access the image will no longer show in the post.

That is why I tolerate the smaller file limitations in Attachment Manager to attach an image file to a post. The image will always be there.

Attached is a photo of the speedometer back. After comparing it to the Chevrolet wiring diagram, I'm still confused. Should the single wire with the black tracer attached to the POS side be switched with the single black & red tracer wire attached to the NEG side of the ammeter?




Now take a look at the wiring manufacturers instructions. Wire #3 - a black & red tracer wire that goes from the voltage regulator should go to the ammeter's NEG side.

Take a look at the voltage regulator diagram in the instructions.

It looks like you have already removed the tracer numbers on the wires. So the YNZ worksheet might not be as much help as you would like.

I suggest you need to trace each wire from the ammeter to the respective connecting points. Then compare that to the full wiring diagram.

I notice that you have a wire with a black tracer only attached to the ammeter. I do not see that in the wiring diagram.

One other point is to confirm the + and - marks on the tape for the ammeter. There are those of us who have managed to reverse those.

I was able to look earlier at the Old Car Manual Project site wiring diagrams and it showed a natural w black tracer running from the negative side to the Batt terminal of the voltage regulator. I just went to that site to post a link and it must have been sold because what used to be there is all gone.

I am getting the same lack of response. I often wondered how long we would have the resource with no apparent financial support for the servers and operating system.

I see one more wire in that picture than on the diagram.

The action seems normal if your battery is down, except that it is backwards. I would expect that hard charging to calm down after a little bit after driving, and I wonder if your regulator is regulating.

Now back to the problem at hand. The wire going to the battery should be on a post all by itself 99 percent of the time. Occasionally manufacturers put the horn over there too. I don't know why. Verifying that the battery wire is all by itself should be easy enough to check.

All the other wires go to the other side. One should go to BAT on the regulator, the rest should be feeding voltage to the car's electrical system.

Once it has been verified that the wire by itself is the one going to the battery, try turning the headlights on with the engine off. If the ammeter goes to "charge", it absolutely confirms what others have said, that the ammeter is hooked up backwards.

One other thing... I would route those wires a little differently. As it is if a nut comes loose, that one big wire would sit there and rub against the oil pressure line. It probably wouldn't wear through, but if it did it would probably cause a fire.

I wouldn't rule out "stolen" without some confirmation from the site owner of a sale.

For some odd reason my laptop still takes me to the original site although many of the links are now broken. The wiring diagram link still seems to be working.
http://chevy.oldcarmanualproject.com/electrical/wiring/index.htm

The link you posted still comes up "NOT FOUND". While you still can get into the site, please let me know which manual you are looking at. Maybe I can locate that manual elsewhere. Thanks

Hawkeye,

If you have an actual or a reproduction 1950 Chevy shop manual there should be a wiring diagram in it.

After all was hooked up and as a last step did you "polarize" ?

Polarize = YES Wiring Diagrams = YES x 2
Am I contact with YNZ and hopefully they will be able to shed some light on this problem.

No. My guess is that #10 with black alone is for a acc., heater, radio, dishwasher, etc., is why it is not in the wiring diagram.

I believe what Tiny saw on the old car site he just miss read. Odd thing though. There are four diagrams. Each a little different but show the same info. Note the attached files. They are reversed BUT show the same hook-up

Did you try the test Bloo outlined. Engine off, turn on lights. Witch way did the needle go. Plus or minus?

All I find, you did everything correct if the above test works out to the minus side.

The wire going to the battery belongs on one post of the ammeter all by itself. All the other wires go on the other post.

If it reads backwards, reverse the posts. Switch all the wires. The battery wire still winds up on a post by itself no matter what.

The mystery about the Old Online Chevy Manual site seems to have been resolved. One of the users over on Stovebolt sent a query to the webmaster of the site. Here is the reply:
"Thanks for getting in touch. It was an internal mis-configuration in our new server. It's fixed now, though they might be sporadic disruptions for the next few days while I move the entire Old Car Manual Project collection over. There's around 700k files.
Please try reloading any pages that don't work, and if you could let me know if there are any persistent problems, that would be helpful too.

Regards,

Rusty"

Excellent!

I agree that the first step is to determine which wiring diagram is applicable to your car. Does your car have the junction block on the instrument panel?

I also believe that the most likely problem is that the wiring on the gauge is backwards. I do not know who put the tape with the +/- marks on the gauge. The posts are often opposite the direction of the needle movement due to the location of the pivot point of the needle.

I noticed that you have a second wire connected to the B terminal on the regulator. What does that connect?

I agree that the wire with the red and black tracer should be a connection between the B terminal on the regulator and the - on the gauge..

One of the wires with the red tracer should be a direct connection to the horn relay (or horn if you do not have a relay).

The other wire with a red tracer does have some junctions within the run. Eventually it will lead to the battery terminal on the starter and ultimately to the + clamp on the battery.

I do not know where the wire with the black tracer should connect. Perhaps is should be on the accessory side of the ignition switch.

Now that I look at your original pictures I have to reconsider my original statement about your regulator working correctly. After you drive a while the battery should be recharged and the ammeter should read just a little off center to the + side. If you took those pictures after driving some distance it does not appear that the regulator is reducing the charge going to the battery

The great ammeter mystery is solved....I hope. I ASSUMED that because the ammeter read + and - that those marked the positive and negative side of the gauge. WRONG!!! I looked at the original gauge and very faintly on the back, you can read BAT on the right side of the gauge. So yes, I wired the gauge backwards. But now a new twist. Why is there a natural wire with black tracers in this picture? After talking with Y N Z wiring, they could not understand the natural w/black tracer wire either. I removed the voltage regulator plate from the firewall and began taking photos. I discovered the problem. When the harness was assembled, someone used a 10 gauge natural with black tracer wire to go from the starter button to the ammeter switch INSTEAD of natural with RED tracers like it should have been. So tomorrow, after I limber up and do some stretches to get under the dash, I plan on reversing the wiring on the ammeter. Thanks for everyone's input and patience. I did not want to just reverse the wires without knowing what they were for first. Fortunately, most of the wires under the dash still have there numbering tags on them. Will let you know the results of this fun time with classic car restorations.

That is great news. I applaud your focus on finding the “why” before blindly charging ahead.

I was thinking about your situation more this evening.. I am still not completely sure I understand the additional black wire under the “B” terminal on the regulator. I do not think it interferes or creates problems. It is just an unusual place to add a circuit.

I am still wondering why there are 3 wires under the one terminal on the ammeter.

One other question is where is the solid black wire that is supposed to connect between the neutral start switch and the starter switch. On manual transmission cars that black wire connects directly to the solenoid from the starter switch.

You do have the natural with red tracer that connects to the ammeter.

Just keep an open mind and work carefully.

If "B" is the same as the "Bat" terminal of the regulator, then it is the best possible place to connect accessories. I agree it was rarely done.

I would also want to know where that extra wire goes.

I don't have a neutral switch on this car. I do not have the natural red tracer wire that should go from the starter button to the ammeter. I will be marking that incorrect color wire so the next person knows. Y N Z chose to run two different wires to the ammeter instead of one. Why, I don't know. The extra wire to the voltage regulator is for the under hood lamp.