VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1933-1936 34 Generator Cut-out

What was the voltage reading on the battery side of the cut-out? We need as much specific information that you can supply.

On the generator side of the cut-out how did you have the positive and negative probes on the meter connected?

On the Generator side I had the ground where it was before and the probe I used on the battery side on right side of the cut-out. It read about 100when I had it on the HOT side, don't know what that means. I left the ground wire where it was and touched the wire I took off the hot wire to the stud on the Generator and on the right side of the cut-out,no reading.

And, where was that?


The battery side of the cut-out is on the left side of the cut-out (towards the radiator), not on the right side.



You are not using the meter correctly or hooking it up correctly from your description. Set your digital meter to DC Volts and select a scale that is about 10 DC volts or higher. With the car running at a higher RPM, place the positive probe (it is the red probe) on the terminal on the cut-out that the wire coming out of the generator is connected to. Place the negative probe (black) on a ground connection on the side of the generator like a bolt on the generator. Make sure that the ground connection is clean so that you will get good contact. Then read the generator voltage.

I'll try it tomorrow but I think I've already done that and no reading.

Practice on your car battery with your digital or analog meter so that you will know that you are using the meter correctly. Set the meter to DC Volts and pick a scale that is higher than 6 volts. Red probe on the positive terminal of the battery and the black probe on the negative terminal of the battery. You should read a little over 6 volts on the digital meter. Same on the analog meter.

To see if you have the meter set correctly try a check on the battery itself. Red port on right to pos and Center port on meter to neg or ground. If the meter reads ok like 6+ volts then move to the generator and test the input voltage. Again red + on the bat terminal on cut-out and black - on a good ground . If still reading 6+ volts then start the car and with it at a high idle move the red + to the opposite side of the cutout. If no reading then either the cut-out or generator is bad. And if any of this is incorrect then I am sure JYD will advise.

Sounds good, I'll try again.

Worked on the 34 and 35 Masters today. Took the Generator off the 35 Master, which worked. Tried both Generators from 34 and all three Cut-outs, none worked. So I figured the Generators must be bad. I then put the Generator off the 35 on the 34 and it did not show a charge either. Put it back on the 35 and it worked. So it looks like the Generators for the 34 don't work but I don't know why the Generator from the 35 didn't work on the 34. I'm still going to send the 34 Generators back to the Generator shop on Wed. But I'm not sure they will work when I put them on the 34.

So did you first try any of the suggestions above and if so what were the results? While it's tough to diagnose problems long distance it's impossible unless we get answers to the questions asked. Could be as simple as the battery hooked up with incorrect ground. Without starting the car put the lights on and then tell us whether the ammeter shows charge or discharge.

Yep, I have been trying to get answers to my above questions as well but so far no luck. As you mentioned, unless we get the answers to our questions it is almost impossible to help.

Jonjet: Sounds like you have another issue causing the problem with charging system since the 1935 generator did not work on your 1934 either. Did you polarize the 1935 generator when you put it on your 1934?

You do have the areas where the bolt goes through and the bolt on the bracket not painted? And the bracket where it contacts the block not painted...so it has a "ground path" to the block? Right? It needs a clean ground path to the block.

Two answers. First, when I pull on the Light Switch on on the 34 it shows a discharge. Second, I'm pretty sure I polarized the 35 when I put it on the 34 but not positive. May have to try it again. As far as the ground, the Generator worked this summer and I haven't painted anything since. As far as the Voltmeter, I gave up on that.

If you put the generator from the 35 back on the 35 and it charges then it is polarized. After you have the generators checked at a shop and they are working OK then you will need to look for a short in the wiring. When you get the generators back from the shop and reinstall them it is best to again polarize them after installing.

Car running or not running when you pull on the light switch? Not running showing a discharge is normal. Running at idle with the lights on the amp meter might show a discharge. With the car running at a higher RPM the amp meter should show a charge. Make sure that the wires on the back of the amp meter are not reversed. It the wires are reversed the amp meter will show a discharge even though the generator is charging. That is where a simple volt meter is extremely helpful because that would tell you immediately if your generator is charging or not charging.

You might want to take a class at your local school on how to use and read a multi-meter. That is one of the most helpful tools you can have when working on the wiring or charging system of a vintage Chevrolet.

Car is not running when I pull the light switch. I could take a class on how to use the Amp Meter but I wouldn't guarantee I could use it. I'll show you a picture of the Amp Meter tomorrow and maybe you can help.

If the car is not running when you put out the light switch the amp meter should read a discharge since the generator is not working because the engine is not running.

Yes, post some photos of your digital and analog multi-meters.

I took the Generator back off 35 and installed it on the 34. Made sure it was polarized, Amp Gauge showed nothing. Put back on 35 showed charging. Here is a picture of the Volt meter (not very Clear). with dial set on 10DC and Red Probe on Bat.Term. on Cutout and Black to ground the needle showed about 100 on the Green scale.

Is the 1934 a Master? If so is the resistor on the back of the light switch burnt out?

The pictures are not clear enough to read. What is the make and model of the meter? We might be able to get a picture and description on line. The meter should have more than one scale and the scale you want to read is the one you select on the setting. So if you have set the meter on the 10DC setting then you need the reading on the 0 to 10 DC scale. I am guessing you are reading the 0 to 250 scale on the meter which is probably about 4 volts according to my elcheapo free H-F meter.

It is a Master. Maybe the resister is burnt out. How do I know if it is? Will that keep the Amp. Gauge from reading? I'm not going to mess with the Volt Meter any more.

The photos of your multi-meter are so blurry that it is impossible to make out any of the details in the photos.

You are not going to like the answer to your question: You can tell if the resister is burned out with your multi-meter.


As mentioned several times previously, the red probe should go on the generator side of the cut-out which will eliminate the cut-out from the charging system so that you can tell if the generator has any output. If you put the red probe on the BAT terminal of the cut-out, and if the cut-out is defective then you will not get a voltage reading so you will still not know if the generator has any output.

If I remember it is the black numbers that you should be using for DC voltage. As suggested above the scale should be from 0 to 10 when you have the setting on 10 volt DC.

There is a Meter like mine on e-bay item no.283353931352. No instructions and I can't find any on line. Can't be that hard to use. I would assume you put it on 50 on the DCV scale but I don't know what the readings mean or where the Dial should be.

Have a look at this youtube video.



Watch for the section where he tests the 18v drill battery. He sets the meter to the range above the expected battery voltage. You would set your meter to the voltage above (but closest to) your 6v battery voltage. You then find the black area in the meter face that is labelled "DC" and look for the range that matches. He uses a 50volt setting in the video so finds the range labelled 50v at the furthest right hand side.

The easiest way to sort out the meter would be to measure the battery voltage on your daily driver car as we know it should be 100% fine. With the car off, follow the video instructions and measure the voltage. You should measure around 12.6 volts on a fully charged 12 battery so look on the meter while using it and see where it is showing you the 12.6volts. Now visualize where the needle will point on a 6v battery - it will be about half way as far IF the battery is charged completely. Do it a couple times so you know the process.

Yes set the dial to DCV 50. About in the middle of the scale you should see 0 on the left and the 50 on right just above the red scale. The markings are 0-10-20-30-40-50. You should be reading a little more than half way between 0 and 10 for your voltage. It appears there is a white marking on the end of the dial which would be the pointer but I can't really tell.