Charging System Troubleshooting--Blown Ignition Light Fuse?

[ACHiPo]

[quote=patrickt;1461837]
Run a fused wire from the ACC terminal of your ignition switch (WHITE wire) to the exposed pin on the ignition switch that had the two green wires on it. The G/R wire should still be attached to the ignition light normally.

I assume you mean the exposed pin on the ignition light not switch?

[ACHiPo]

Talked to Bob. I am going to modify the VR connector to emulate the older design with out an ignition light, removing the "I" wire from the connector and jumpering "A" to "S". I will reinstall the fuse (which may blow again) so maybe I'll regain the use of my tach. Even if the fuse blows, I should be able to drive the car and have it charge (hopefully)!

[patrickt]

Originally Posted by ACHiPo

I assume you mean the exposed pin on the ignition light not switch?

Yes, that was a typo.

Originally Posted by ACHiPo

Talked to Bob. I am going to modify the VR connector to emulate the older design with out an ignition light, removing the "I" wire from the connector and jumpering "A" to "S". I will reinstall the fuse (which may blow again) so maybe I'll regain the use of my tach. Even if the fuse blows, I should be able to drive the car and have it charge (hopefully)!

Alright, that's pretty easy to do and we can always switch it back.

[ACHiPo]

Well something kinda worked!

I removed the "I" wire from the VR connector, jumpered the R/Y and W/B lugs and reconnected it to the VR. I replaced fuse 3, reconnected the ignition lamp, and removed the fused jumper from the ignition switch.

I started the car, the ammeter rose to 15A, and rose and fell as I feathered the throttle. I turned on the headlights and the ammeter dropped to 5A. Turned off the lights and the ammeter rose back to 15, then the engine died. This whole process lasted a little over a minute, but the charging system seemed to work the entire time.

I restarted the engine, but the ammeter didn't move. I turned on the lights, and the ammeter dropped to -10A, and back to 0 when I turned them off. I shut off the engine and checked fuse 3--it was blown again. Guessing it blew when the engine died or when I restarted it.

I don't understand why the fuse would blow since the "I" was disconnected, basically taking the ignition light out of the circuit?

I ran Patrick's test (I think?), removing the jumper between A and S on the VR connector and grounding the A (Y/R) wire to the block. I removed the fuse (even though it was blown), pulled off the double wire, and reconnected the fused jumper to the ACC terminal of the ignition switch. Turned the key to "ON". Nada. Started the engine. Nada.

[patrickt]

Originally Posted by ACHiPo

I don't understand why the fuse would blow since the "I" was disconnected, basically taking the ignition light out of the circuit?

I would guess that the short to ground is upstream on the Green line. Perhaps at the tach, or the wipers, or the wiper switch. Leave Fuse 3 out of the car entirely, check and replace any other fuses that may have blown, and start the car up again with the modification that you made to the VR at Bob's direction. Run the engine and check your system voltage with headlights on, etc., and see if you have a nice 13 or 14 volts, which would indicate that the system is charging normally.

[ACHiPo]

Originally Posted by patrickt

I would guess that the short to ground is upstream on the Green line. Perhaps at the tach, or the wipers, or the wiper switch. Leave Fuse 3 out of the car entirely, check and replace any other fuses that may have blown, and start the car up again with the modification that you made to the VR at Bob's direction. Run the engine and check your system voltage with headlights on, etc., and see if you have a nice 13 or 14 volts, which would indicate that the system is charging normally.

The only fuse that blows is Fuse 3. I'm going to disconnect the tach. I don't know if I can get to the wiper switch or heater. I will check charging voltage assuming I can get things to run in Bob's configuration.

The system charged normally for about 60 seconds with Bob’s configuration. It doesn’t seem that charging happens with fuse 3 blown.

[patrickt]

Originally Posted by ACHiPo

The only fuse that blows is Fuse 3. I'm going to disconnect the tach. I don't know if I can get to the wiper switch or heater. I will check charging voltage assuming I can get things to run in Bob's configuration.

The system charged normally for about 60 seconds with Bob’s configuration. It doesn’t seem that charging happens with fuse 3 blown.

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.

[ACHiPo]

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]

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]

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]

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]

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]

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]

A bit of progress. I've got the voltage stabilizer out of the dash. There is about 115 Ohm resistance between the two lugs (seems high?), but there is no continuity to the case or ground which I would expect if it is the cause of the short.

Thoughts?

[ACHiPo]

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.

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?

[patrickt]

Originally Posted by ACHiPo

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

Yes. If that VS is the problem, we'll just leave it there and install a new one somewhere else that is convenient and then run wires to the two original wires.

[ACHiPo]

Well, the voltage stabilizer is not the problem, but the weirdness continues.

Removed the stabilizer, put the two green wires together, and returned everything else to stock (ignition bulb, fuses, VR connections). In the process of this I inspected all the firewall fuses and noticed that fuse 4 was in fact blown. I replaced both fuse 3 and 4.

Turned the key to "ON" and the radiator fan turned on immediately, with the ammeter dropping appropriately. No ignition light. Not sure if I mentioned it, but last week the manual fan switch broke, so I couldn't turn the fan on. Not sure why a normally open switch is now closed? Started the engine and the ammeter didn't move (no charging). Shut down the engine and flipped off the battery switch.

Inspected the firewall fuses. Fuse 3 blew again. Fuse 4 is intact.

Think I'm gonna go binge watch the Twilight Zone!

[patrickt]

Originally Posted by ACHiPo

Turned the key to "ON" and the radiator fan turned on immediately, with the ammeter dropping appropriately. No ignition light. Not sure if I mentioned it, but last week the manual fan switch broke, so I couldn't turn the fan on. Not sure why a normally open switch is now closed? Started the engine and the ammeter didn't move (no charging). Shut down the engine and flipped off the battery switch.

The radiator fan circuit does not run through the ignition switch. That's so the fans can come on when they need to (usually through the thermostatic switch in the lower radiator hose) even if the ignition is turned off. That is really strange that it would come on with the ignition switch. Could you have hit something? Or pulled something loose?

[ACHiPo]

Originally Posted by patrickt

The radiator fan circuit does not run through the ignition switch. That's so the fans can come on when they need to (usually through the thermostatic switch in the lower radiator hose) even if the ignition is turned off. That is really strange that it would come on with the ignition switch. Could you have hit something? Or pulled something loose?

Getting to that voltage stabilizer and getting it out were very difficult. I may very well have hit something. The question is what and how do I fix it.

Gonna take a break and regain my composure. Will hit it again early tomorrow morning. Whatever troubleshooting suggestions you have I will greatly appreciate.

I'm thinking that figuring out the fan thing will be first as I suspect I did something fishing around. Next I think trying Bob's configuration could be good, although it seems I need to figure out and fix why fuse 3 (and 4) fails.

Maybe I'll try out my short finder.

[patrickt]

I would:

1) Put the two wires back on the VS.

2) Look around as best you can for anything that you hit that, maybe, would be around the manual fan switch. I'm actually having trouble conceptualizing how that fan could even come on by just turning on the ignition switch.

3) Implement Bob's wiring change that eliminates the need for the ignition light.

4) Leave Fuse #3 out of the fuse box. We'll tackle that short last.

5) Start the car, see if you're charging properly (the ignition light is disconnected so don't worry about that), and see if the fan comes on or stays off.