1967 c30 no charge and weird(?) problems

[flatbed67]

No charging on my C30 with original external regulator.
new bearings and brushes, I measured the six big diodes to my best knowledge.
when engine is running, no charge when shorting field to +.
the weird thing is the alt light is out when ignition is on and engine not running, and on when key is turned backwards to accessories.
I have put in an original(style) new ignition switch, exactly like the old one.
Also the alt right is on, even when the regulator and alternator are disconnected, and key in acc.
I'm out of ideas...

[VetteVet]

........................

Originally Posted by flatbed67

No charging on my C30 with original external regulator.
new bearings and brushes, I measured the six big diodes to my best knowledge.
when engine is running, no charge when shorting field to +.
the weird thing is the alt light is out when ignition is on and engine not running, and on when key is turned backwards to accessories.
I have put in an original(style) new ignition switch, exactly like the old one.
Also the alt right is on, even when the regulator and alternator are disconnected, and key in acc.
I'm out of ideas...

Your alternator light is turned by voltage from the ignition switch pink wire going to the fuse panel, and then from the fuse panel to the gauge cluster plug on terminal 7. It goes through the light and back out of the cluster panel by way of the brown wire on terminal.

Here are the wiring diagrams to show this.

From the key switch via the pink wire. It's about 5 down from the top.




From the fuse panel via the pink wire to the cluster connector.




The the brown wire on terminal runs to the firewall block behind the fuse panel, goes through the firewall block, and goes to the external voltage regulator to terminal "f '. This wire should have 12 volts on it when the key is on and no volts with the key off. Check it with a multimeter if you have one.

Here is what it looks like.





Notice the other three wires on the regulator. Red white and blue.

The red wires is a power wire from the alternator, battery power junction.

When you turn the key on the brown and white wires are connected and the blue and red wires are connected. They send power to the back of the alternator via the blue and white wires to the plug in at the alternator.

The white wire is connected to the R terminal and the blue wire is connected
to the F terminal.

The white wire is grounded through the alternator diodes and when the key is turned on the light is grounded and should come on. Then when the alternator starts charging it puts 12 volts on the light wire and with 12 volts on each side of the wire, the light loses it's ground and goes out, indicating that the alternator is charging. At least that's how it's supposed to work.

If your light is not coming on when you turn on the key, then it is not getting power from the fuse panel, or it is not getting a ground through the alternator.

You should check for 12 volts at the white wire, at the alternator when you turn the key on. The with the alternator unplugged and the large red wire off check for continuity through the alternator between the R terminal and the alternator body.You should get a small amount of resistance. This is for the ground side of the light that turns it on when you turn the key on.

If you're not getting these readings then it could be as simple as the regulator body is not grounded to the sheet metal or it isn't working.

When you turn the key switch to accessory and the light comes on it is probably getting power from the accessory terminal, if you notice a resistance wire along with the accessory wire. This resistance wire is connected to the same place as the wire from the light at the firewall behind the fuse panel. This resistance wire is a back up for the charging light in case the bulb blows on the light. In order to excite the alternator charging circuit, it needs to get some resistance from someplace, and the charging light has 10 ohms of resistance in it's filament, and the resistance wire also has 10 ohms of resistance. They are wired in parallel in case the bulb blows on the light. The black arrows on the second diagram show these two wires.

You will need to check the clstr pnl fuse and be sure it's good and the connections on it are good. If your fuel and temperature gauges work then it is probably OK.

Be sure and check the ground on the alternator body and it should have a ground wire to the regulator as well.

This should give you something to start on.

[flatbed67]

Thank you very much, VetteVet. That was a lot of good info in that package. I might look into it deeper at some point.
There wasn't anyting wrong with the alternator light, it just didn't get any ground through the regulator, so I think it's faulty. I think the alternator itself might be ok, and have to try and get a new regulator at some point.
As I am in a hurry to get the truck in usable condition, I put in another alternator for now. I wired in the brown wire from the regulator, to the D+ on the alternator, and now the light turns on with the ignition key, and goes out when the alternator starts charging.
This is the easy way out, and I am a bit embarrassed, but I can't get a new regulator fast enough to get the original alternator to work.

[VetteVet]

Originally Posted by flatbed67

Thank you very much, VetteVet. That was a lot of good info in that package. I might look into it deeper at some point.
There wasn't anyting wrong with the alternator light, it just didn't get any ground through the regulator, so I think it's faulty. I think the alternator itself might be ok, and have to try and get a new regulator at some point.
As I am in a hurry to get the truck in usable condition, I put in another alternator for now. I wired in the brown wire from the regulator, to the D+ on the alternator, and now the light turns on with the ignition key, and goes out when the alternator starts charging.
This is the easy way out, and I am a bit embarrassed, but I can't get a new regulator fast enough to get the original alternator to work.

I though later, why didn't I suggest that you ground the brown wire that goes to the regulator and see if the light works. /even better would be to ground the white wire to the alternator.

If you do get one of the digital ones. Of course I would suggest that you convert to the internal model alternator,SI or CS, for not too much more than the cost of a new regulator.

There are a lot of people who view our posts that benefit from all the information that gets posted. I like to provide as many details as I can.

You should see my pm account.

[flatbed67]

I wasn't going to convert to anyting, but the original alternator. Especially, since I had rebuilt it the best I could. Apparently it wasn't enough, because the alternator lamp wouldn't light up when I turned on the ignition, not would the alternator charge, when I ran a + lead to the field with the engine running. Apparently there was someting wrong with it anyway.
I have read numerous threads like this one, and all have the same depressing ending: The alternator has been changed to an internally regulated one. This sorry ending doesn't do much for those who want to get the old one to work properly.
I feel guilty and am very sorry...

To further add insult to injury, the "new" alternator is a DelcoRemy, made in France. It's almost a blasphemy.

[VetteVet]

Originally Posted by flatbed67

I wasn't going to convert to anyting, but the original alternator. Especially, since I had rebuilt it the best I could. Apparently it wasn't enough, because the alternator lamp wouldn't light up when I turned on the ignition, not would the alternator charge, when I ran a + lead to the field with the engine running. Apparently there was someting wrong with it anyway.
I have read numerous threads like this one, and all have the same depressing ending: The alternator has been changed to an internally regulated one. This sorry ending doesn't do much for those who want to get the old one to work properly.
I feel guilty and am very sorry...

To further add insult to injury, the "new" alternator is a DelcoRemy, made in France. It's almost a blasphemy.

I hope I have not offended you by suggesting that you go to an internally regulated alternator. I am a big fan of original parts. There are many on here that wouldn't change for nothing. I was only thinking that it would be less costly to invest in an internally regulated alternator, if you were so inclined, before you bought the external regulator. If you don't plan to add a lot of accessories the external setup will work quite well.

There's not much that can go wrong with the alternator, diodes, brushes, and the bearings. There are you tube videos on rebuilding them that are very good. I thought from your last post that you were just needing a new regulator. Did you get one and it did not fix the problem?

[flatbed67]

You didn't offend me in any way, VetteVet.
I'm not even into original parts per se, but it just annoys the heck out of me when I can't get something to work, especially when I have already started repairing it. It's like giving up and taking the easiest way out.

For the time being, though, my truck works, and the battery gets its charge from the Delco Remy alternator I mounted to the original mounts the other day.
I hope that I get renewed energy, to start working on the old externally regulated alt again soon.

[VetteVet]

I have a feeling you'll get it fixed. Post back and keep us updated.