Charging System Troubleshooting--Blown Ignition Light Fuse?

[DanEC]

Evan - you can remove the steering wheel, loosen the brackets holding the steering column to lower it as much as possible, wrap the column to protect the finish, and remove the screws holding the panel and lower it to where the column will support it. Just don't completely unscrew the column bracket - lower it as much as possible. There are so many cables, wires, etc connected to it that it won't go anywhere. Then as Patrick said you can access it from the top.

Wish I could help more on the root issue but Patricks on the case so he will get it figured out - I have confidence in him.

On the broken visor - don't sweat it - gives you a reason to order those from Finish Line with the gold Cobra label like the originals.

[patrickt]

Originally Posted by DanEC

Wish I could help more on the root issue but Patricks on the case so he will get it figured out - I have confidence in him.

Wait 'til he sees my bill.

[ACHiPo]

Originally Posted by DanEC

Evan - you can remove the steering wheel, loosen the brackets holding the steering column to lower it as much as possible, wrap the column to protect the finish, and remove the screws holding the panel and lower it to where the column will support it. Just don't completely unscrew the column bracket - lower it as much as possible. There are so many cables, wires, etc connected to it that it won't go anywhere. Then as Patrick said you can access it from the top.

Wish I could help more on the root issue but Patricks on the case so he will get it figured out - I have confidence in him.

On the broken visor - don't sweat it - gives you a reason to order those from Finish Line with the gold Cobra label like the originals.

Dan,
I was able to drop the dash about 3/4" which actually made a huge difference in being able to fit my hand up behind the fuel gauge so I got the gauge put back together. I was not able to get the two dashboard end screws (behind the doors) started and gave up before I hurt the car or me. Will also check with ERA on tips to get the dash into just the right position to get those screws started.

Unfortunately the visor that broke was from Finish Line with the gold engraving. Replacement and a spare are ordered. That was easy enough.
Evan

[patrickt]

Here, this test will take less than five minutes, requires no wire cutting and, if successful, will make your car drivable (excluding wipers, gauges, and heater).

[ACHiPo]

Originally Posted by patrickt

Here, this test will take less than five minutes, requires no wire cutting and, if successful, will make your car drivable (excluding wipers, gauges, and heater).

I got a chance to try Patrick's diagnostic, and I got something, but not what I hoped for.

Removed the ignition light from the dash for access. Pulled the double green wire off the ground spade of the light socket. Ran a fused jumper between the accessory terminal on the ignition to the grounded lug of the ignition light.

Turned key to ON position. No light.
Started engine and light came on while cranking and extinguished when engine started.
Ammeter was slightly negative (~1A) with engine running. Turned on headlights and ammeter dropped to ~-12A. Revved engine, but ammeter didn't budge.

I'm sure I learned something, just not sure what. Maybe that I can definitely eliminate the gauges as a short path?

[patrickt]

That's progress. For the next set of tests, you will leave the double green wire disconnectied from the light for everything below.

1) Remove the G/R wire from the ignition light but leave your fused jumper wire running to the light. Turn the ignition switch ON but do not start the car. Touch a known good ground lead to the exposed pin of the light and observe that it illuminates. Then, using a VOM, test for either a) 12v+, b) 12v-, or c) neither one at all at the disconnected G/R wire. Report the findings.

2) Plug the G/R wire back on to the ignition light. With the ignition ON, and the car not running, the light should be "ON" but you report that it is not. Try running a known good ground wire to the alternator and voltage regulator and touch different spots on both those components just to see if you can get the ignition light to illuminate. For instance, touching a known good ground wire to the VR case and making the light come on each time you did that would be a really nice sign. Report back.

3) Insert a fuse in to Fuse #3 and turn the key ON, but do not start the car. See if your gauges, heater, and wipers work or if you blow the fuse doing that. Report back.

We are making progress.

[ACHiPo]

Pat,
This looks great! Talking to Bob I checked the ignition light for short to ground, but it's good. He suggested I try to duplicate a symptom I noticed Friday next--with the fan unplugged and car running, the ammeter swung positive when the fan relay was energized.

After that I was going to start checking for shorts to ground at the fuse box, then into the loom at this point, but will give your idea a try first. It will likely be tomorrow evening before I get a chance.

Evan

[patrickt]

And if that test is successful, then the quick way to find the short would be to invest in a short and open finder tool. You can get fancy ones, or there's a couple on Amazon for less than $30. Like this: https://www.amazon.com/allsun-Automo.../dp/B07BC4X28Y

[ACHiPo]

I used the DVM rather than trying to see the ignition light since I'm working alone.

Ignition light side terminal grounded to block, G/R wire connected to ignition light center terminal. DVM clipped to ignition light center terminal.

With ignition "on" (no 3 fuse):
Light to VR ground 0V
Light to alternator case 0V
Light to alternator Batt terminal 13.7V
Light to all other alt terminals 0V

Turned key off, inserted fuse, turned key on. Alt spiked to -15A and fuse blew. Light did not illuminate.

[ACHiPo]

Some additional data. Not sure what to make of it other than there is definitely a connection to ground on the fuse 3 circuit, and it's not between the ignition switch and the fuse (that tests as open). All tests were made with the battery cut off in the "off" position. The ignition light is out of the circuit.

Testing the right side of the fuse terminals to ground:
1 Open
2 Open
3 0.7 Ohm
4 Open
5 Open
6 1 Ohm
7 0.7 Ohm
8 0.8 Ohm

[hauss]

Try a different battery, I had a internal short once and it gave me hell. Sounds like it may be your problem. Also it is easy to do .

[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)!

[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!

[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]

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?