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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.

Hawkeye,

Thanks for continuing to share details about your wiring. The wiring for the under-hood light sure makes sense.

I'm still a little confused about the wiring to the starter switch. The wiring diagrams I have checked show an 8 gauge black wire going to the starter switch from the solenoid, not a natural with black tracer. I agree that there is also an 8 gauge natural wire with red tracer connected to the starter switch. That wire is connected to the battery terminal on the solenoid. The 10 gauge natural wire with red tracer that goes to the ammeter is connected to that 8 gauge wire.

I am still trying to determine the third wire (natural with back tracer) on the one post of your ammeter.

What color wires are connected to the terminal on the starter solenoid?

Like you said, it is confusing to me for sure.

Attached is a photo of where I currently am and I believe the wires are correct. If you look closely, you can see a + on the speedometer housing. I wish I had see that sooner. Anyway, to answer an earlier question. Both wires coming from the solenoid are natural with red tracers. Y n Z either look creative license or did not want to go get a new supply of the correct color wire. The red tape on one of the wires is my version of a natural wire with a very big tracer. Tomorrow, I will put back everything that I have to remove just to get to this special place. Will update you when I can.

I imagine you are ready to finish this puzzle and enjoy your pride and joy. Really nice work and outcome.

Would you please answer this one question inquiring minds want to know. The nat. with black wire you added the red tape to, what number or letter is on that wire AND what did the instruction sheet say about that number/letter?

Sorry it took this long to reply, but I had to upgrade my old computer with a new one. It took way too long to transfer all of my photos from one computer to the other. Anyway, to answer your question about the wire with the red tape on it, that is wire #19 and it goes from the + side of the ammeter to one side of the starter button. The wiring instructions do not show that, there was a tag hanging from this wire instructing where it goes. I did separate the two wires per a phone conversation with YnZ, but I didn't' have to do this. I added a terminal and that's why it looks that way.





After looking at the finished product and reviewing the instructions, I am now wondering why I did some of these connections. I don't have the telephone conversations written down to back up my work. For example, why is the black wire with yellow tracers going from the battery side of the junction block to the headlight switch instead of the( - )side of the ammeter?







I started up the car and ran it for about 5 minutes but the ammeter still shows discharging. Does this take some running time to self correct?

Thank you for the follow-up. Odd that they put that jumper on the #19 over to the start button when it is not shown in the '50 diagram. However it is shown just like that on a '51 diagram.

I have been having a hard time understanding the '50 diagram because I do not see the junction block as you have. It does not show a block with a Batt side or a switch side and what wires go to or leave from each. At least that I can understand.

The black w/yellow it picking up power from the light switch instead of the ammeter to feed something? Don't think it makes any difference.

With the motor running and you increase the rpm to say 1500 or so, does the needle move towards the C (charge) side?

Sorry that I cannot be more help at this point. I know this is painful especially now that the tracer numbers are removed.

I suggest that you need to print out the factory wrong diagram and start doing a wire to wire comparison to what YNZ sent you.

Like Russell, I am not able to locate the junction blocks you show in your pictures in the wiring diagram that is in the manual. Also, you should have the power wire to the horn relay on the + ammeter terminal. You could damage the ammeter sending all the horn current through it.

The #4 red tracer wire from the horn relay is connected to the (+) side of the ammeter per GM's wiring diagram & YnZ's.





Also attached is a photo of the instruction sheet from the GM Wiring Block. Because this was an accessory, the dealer installed it and probably did not show up on the general wiring diagram.

Thanks for the picture in your latest post that has the wires numbered. If I am interpreting that correctly I think I see some problems. Basically you a have the ammeter wired backwards.

Wire #3 should be on the - post of the ammeter. That is from the battery terminal on the regulator. That is the power coming from the generator to recharge the battery through the ammeter.

The wire with the red tape (#19) should be on the + post of the ammeter. It should be coming from the large post on the starter solenoid. It should not be coming from the starter switch. It really connects back the battery.

Wire #4 should be on the + post of the ammeter. That really just uses the + post on the ammeter as a way to jumper from the battery to the horn relay. That way the power to blow the horn does not go through the ammeter.

I am still confused about the wire #20 situation if wire #19 is really from the starter switch. If #19 is from the large post on the solenoid then #20 should be on the + post of the ammeter. That connection uses the + post as jumper between #19 and #20 to get power to the starter switch. That way the ammeter does not measure the power drain to close the starter solenoid.

Rusty, I think I need some clarification. The ammeter has BAT on the back side which I assume means POSITIVE in the 6 volts sense. The (+) on the speedometer housing reflects the face of the ammeter and means the system is CHARGING. If this is correct, then the #3 red & black tracer wire coming from the voltage regulator is in the correct position - on the BAT side (POSITIVE) of the ammeter. I need to go thru this problem one wire at a time so the other suggestions you made will be looked at later.

I believe you made a mistake with your labeling in the picture. That #20 is #19 as shown in another picture above. What you have as #19 is merely a jumper to the start switch as you described above as having a tag on it. Right?

Now, erase that "+" mark! Mark the letters BAT if that is what you see! You have already changed the wires to the new marking you discovered. Done!

Fully charge the battery. Now do the test recommended by Bloo. Don't start the car! Turn on the lights! What does the amp gage do? Does it point to D or C????? If it points to D as it should, done. If not, then their is a problem somewhere! DO THIS TEST, PLEASE.

Now start the car, rev up to 1500/1800 or so. Does the gage show towards the D, stay in the middle, or towards the C. Make sure nothing is on, including the interior light.

I don't mean to be disrespectful in any way. I want this resolved nearly as bad as you.

I did turn on the lights with the door closed and the ammeter did read discharge. (See my post back on 8/15). Then I did start the car and run it at a higher PRM and the ammeter reads "D". The (+) above the ammeter is stamped into the metal assembly so I cannot remove it. After climbing under my dash for the ### time, I took more photos and determined that I did label the photo incorrectly. Here is the corrected labeled photo.






If you look very close, you can almost see the BAT in this photo. The camera is not as good as the human eye.

THANK YOU!!

So the BAT stud is the stud under the + mark, good to know. I am of the belief you now have ALL the wiring done correctly as per the YnZ instructions.

What now?

Guess you need to find out if you are getting voltage (and how much) out of the generator and through the voltage regulator to that #3 wire to the amp gage?

Here is a really crazy idea to consider.. Maybe the generator is not producing enough current. Have you had it tested?

Sorry if that was in an earlier post.

The wire from the Bat terminal on the regulator should connect to the Bat terminal on the ammeter. I do not know how that aligns with the +/- on the housing.

NO! The BAT stud on the ammeter is behind the (-) discharge. If you are sitting in the drivers seat, it would be on the left side of the ammeter. THAT"S why the (+) on the metal housing is so confusing. That (+) must indicate the location of the charging side of the ammeter and nothing for voltage.

LOOK AGAIN, if that is the case, it is now wired backwards and you had it right the first time. #3 goes to the BAT post wherever it is.


Early you said the above. Right side from the front or back? Gage upside down or right side up. Look again.


You have a voltage issue.

Attached is a photo labeled with all the information regarding the wires on the ammeter. Also attached is a Chevrolet Wiring Diagram for 1950. The only wire on the (-) NEG side of the ammeter is the #3 red & black tracer wire going to the BAT side of the voltage regulator. The rest of the wires are attached to the (+) POS (BAT) side of the ammeter. I am assuming that the BAT terminal on the ammeter is (+) POS. Am I still missing something???


1950 Chevrolet Wiring Diagram

Post a picture of your old amp gage. Set it upright on something. Take a shot from the front and move around and a shot from the back! Trace over the BAT letters so that it shows in the shot. Don't get too close. Make sure the whole gage can be seen.

I can't find my tripod so these photos are a little blurred. Here you go.

Well my final verdict is in. The YnZ instruction sheet reads to hook #3 wire from the reg. to - on the ammeter for a very good reason. The stub on the - side IS the battery connection side as indicated in your photo of your gage. With ALL this evidence before me I have to vote that your ORIGNAL hookup was correct. Looking from the backside the #3 should be on the right stud all by itself. ALL other wires #4, #19 and the #19 jumper to start button should be on the left stud. Just as you had it in your very first photo at the start of this thread.

All the above is with the assumption that the replacement ammeter is identical to the original.

In conclusion, my thinking leads me to believe you have a voltage issue. I would do as I indicated before, to check the gen. and reg. to see that they are working correctly and what voltage is leaving the reg. in that #3 wire at above idle rpm.

Sorry you had to go through all of this, but is seems to be part of the "old car game", speaking from my own experience. Good luck!

I agree with the thinking that there is not enough current being produced by the generator. Even if the ammeter is connected backwards but properly wired the needle should move to the other side of neutral if there was enough current output from the generator.

Measure the voltage 3 places with the engine running at about 1000 rpm. Measure where the armature wire connects to the generator, measure at the Bat terminal on the regulator, and measure at the battery.

Let us know those readings.

Thinking long, think wrong. Started to second guess myself then I came across this post.
https://www.chevytalk.org/fusionbb/showtopic.php?tid/335536/
So just maybe I am right. Time will tell.

The wires are where they are supposed to be. The mistake I made was thinking that the ammeter is like a volt meter - it is not. Anyway, I did the testing that was suggested and here is what I came up with. Because my Volt Meter is part of my Dwell & Tack Meter, I had to guess at what 1000 rpm's was. Different connections are involved. At the battery, the reading was 7 volts. At the voltage regulator, the reading was 7 volts. At the generator, the reading was between 6 & 7 volts. Attached is a photo of where the wires are currently at. Thanks to everyone who added their two cents, their working experience & general interest in trying to help me solve this problem. Something that I had not noticed until taking this photo was the - marking just above the red & black tracer wire on the right. I had see the + on the left but because the wires were in the way - surprise.

So now we have come full circle. Back to the beginning of this thread. It started with:
When I look closely at the top pic where you say the needle is just touching the edge of the - mark.

Looking at the second pic you said the needle has clearly moved toward the + somewhat. Did you mislabel the two pics.

You say, when stopped the needle moves to the middle. Is this a problem?

I honestly do not know. Doesn't seem right to me. When you were checking the voltage as you described above, did you happen to notice where the needle was? You indicated you have 6/7 volts in the system so I would think it would be centered or slightly to the charge side from starting the motor if the voltage regulator is working correctly.

Just drive and enjoy for a while but keep a eye on everything. Good luck!