Charging System Troubleshooting--Blown Ignition Light Fuse?

ACHiPo · #1 (**permalink**) 05-18-2019, 08:48 AM

Quote:

Originally Posted by patrickt

With Bob's new configuration, you do not need a fuse in holder #3. You only need that fuse to charge with the previous "indicator light" configuration. The fact that the circuit on fuse #3 was in the process of faulting out can give you confusing results, so you should dismiss that until you've tested further.

Remember that Green wire also runs to the wiper motor over on the passenger side foot box. That plug is really easy to pull, so go ahead and pull it when you're ready to trace for the fault on the two branches of Fuse #3. But I would first test Bob's new configuration, all the while leaving Fuse #3 completely out. The only way Bob's configuration won't work is if there is a bad VR, a bad alternator, or a bad connection between the two. I think it will charge fine. In fact, I think I'm in a position as to guess what happened to cause all this mess, but I'm going to hold that card close to the vest for now just in case I'm wrong.

Patrick,
If fuse 3 is not required in Bob's configuration to charge, why did the car charge when there was a fresh fuse in # stop charging yesterday and the fuse was blown?

I did receive my short tester, but I'm not quite ready to go down to that level of detail.

Just got off the phone with Doug. One thing not shown on the schematic is a voltage shunt on the fuel gauge. I think, Patrick, this is a similar circuit to what you retrofitted? He suspects that may be the issue, and also since it's installed, the test I did to isolate the fuel gauge did not in fact remove the rest of the circuit. Just wish it was a little easier to reach up in there and access that stuff!

patrickt · #2 (**permalink**) 05-18-2019, 08:59 AM

Well, I can't be really sure until you retest with fuse #3 out. If everything is wired exactly as the schematics for a non-indicator light have all shown for the last 75 years, then the only positive feed that goes to the voltage regulator is coming from fuse #4. That feed from fuse #3 was only to show the indicator light and excite the VR. If you are not using the indicator light then the change in the feeds to the VR gets everything going. BUT, now that I hear that there might be wiring under there, that is on the green line, of which I am totally unaware, well that puts a new spin on the game.

Did Doug tell you where he mounted that "shunt," which sounds like it is a 10v Smiths regulator just like what you see in my pic. Yes, that would be a prime candidate for failure.

ACHiPo · #3 (**permalink**) 05-18-2019, 09:37 AM

Quote:

Originally Posted by patrickt

Well, I can't be really sure until you retest with fuse #3 out. If everything is wired exactly as the schematics for a non-indicator light have all shown for the last 75 years, then the only positive feed that goes to the voltage regulator is coming from fuse #4. That feed from fuse #3 was only to show the indicator light and excite the VR. If you are not using the indicator light then the change in the feeds to the VR gets everything going. BUT, now that I hear that there might be wiring under there, that is on the green line, of which I am totally unaware, well that puts a new spin on the game.

Did Doug tell you where he mounted that "shunt," which sounds like it is a 10v Smiths regulator just like what you see in my pic. Yes, that would be a prime candidate for failure.

Doug told me it's a 3/4" x 1 1/2" silver box that he tucked up between the gauges. It came with my fuel gauge from Nissonger. Since Doug wasn't familiar with the gauge, he just installed the shunt since it came in the box with the gauge. I assume it's a Smiths stabilizer.

I just pulled the steering wheel, removed the foot box fan switches, and dropped the dash to better see under there. I sure don't see it. I need to get ready to go out, but will be back at it later this afternoon.

Here's a photo of the Smiths stabilizer I pulled from Google. It's not what I was looking for, so I will look again this afternoon. Man it's a jungle of wires and connectors up there!
https://i.ebayimg.com/images/g/Gi8AA...gI1/s-l300.jpg

patrickt · #4 (**permalink**) 05-18-2019, 11:28 AM

Yes, be on the lookout for something like this. As I recall, mine said it had to be mounted to a grounded location, so look for a mounting on the aluminum. I mounted mine over by the MSD unit above the passenger's feet. Doug's a pro, and does stuff in a very logical, predictable manner. Take some pics, I'm curious as to where he might have tucked it in.

ACHiPo · #5 (**permalink**) 05-18-2019, 05:52 PM

Quote:

Originally Posted by patrickt

Yes, be on the lookout for something like this. As I recall, mine said it had to be mounted to a grounded location, so look for a mounting on the aluminum. I mounted mine over by the MSD unit above the passenger's feet. Doug's a pro, and does stuff in a very logical, predictable manner. Take some pics, I'm curious as to where he might have tucked it in.

Patrick,
I found it! It is bolted to the back of the water temp gauge. I was looking for a silver part. The problem is the silver faces the dashboard so what I can see is the brownish circuit board.

Now the question is what do I do with the two wires that are connected to it when I disconnect them?

Evan

patrickt · #6 (**permalink**) 05-18-2019, 06:16 PM

Quote:

Originally Posted by ACHiPo

Now the question is what do I do with the two wires that are connected to it when I disconnect them?

Pull both wires off the voltage stabilizer and connect them to each other. You will then have 12v going to your gauges instead of 10v, but it will eliminate the fault, if that was the problem. If the fuse no longer blows, then you found it and can replace it in a convenient location. Is the fuel gauge the only electric gauge you have? (I see cap tubes...)

ACHiPo · #7 (**permalink**) 05-18-2019, 06:31 PM

Quote:

Originally Posted by patrickt

Pull both wires off the voltage stabilizer and connect them to each other. You will then have 12v going to your gauges instead of 10v, but it will eliminate the fault, if that was the problem. If the fuse no longer blows, then you found it and can replace it in a convenient location. Is the fuel gauge the only electric gauge you have? (I see cap tubes...)

Will do. The fuel gauge and tach are electric (as is the ammeter obviously).

Off to check things again without the voltage stabilizer. I sure hope I don't have to put that thing back in, as there's no way I can install it back where it was.

Quote:

Originally Posted by patrickt

If the fuse no longer blows, then you found it and can replace it in a convenient location.

Do you mean replacing the voltage stabilizer in a convenient location?