Charging light no going out, Exciter Wire...Or?

[Heron]

Charging light staying lit even after appropriate rev level has been maintained. Battery brand new(and putting out proper CCA's) and alternator checks out. Plug at the alternator was cleaned and lubed with dielectric grease.

I've read in places about this exciter wire but I cannot find what I should do to remedy it. Or, is this even the issue?

There was a family of mice in this truck. I've found some wires chewed but have repaired anything obvious.

[RustyCaddy]

A stock alternator needs the exciter wire working, might need a good going over (under rated and easily corroded VW wiring).

[TylerDurden]

If the alternator light stays lit after the engine is running (and revved) there is probably a short in the wire to ground. That would probably also keep the alternator from working.

I'd disconnect the exciter wire from the alternator terminal and test the system by momentarily jumpering 12v to the terminal on the alternator when the engine is running/revved... the alternator should start to output.

If that works, I'd trace back the exciter wire to find the short, or just run a new wire from the cluster connector.

[Heron]

If the alternator light stays lit after the engine is running (and revved) there is probably a short in the wire to ground. That would probably also keep the alternator from working.

I'd disconnect the exciter wire from the alternator terminal and test the system by momentarily jumpering 12v to the terminal on the alternator when the engine is running/revved... the alternator should start to output.

If that works, I'd trace back the exciter wire to find the short, or just run a new wire from the cluster connector.

Is this covered in the Bentley? Not sure what wire is the exciter within the plug(3 terminals). Where does it go in the cluster?  Could it have anything to do with a bad ignition switch?
I know on my 09GTI I had all kinds of gremlins when the ignition switch was bad.

[libbydiesel]

Exciter wire is typically blue.  The wire goes to the battery light.  It is shown on the various wiring diagrams.  It would not typically have anything to do with the ignition switch. 

[Heron]

Exciter wire is typically blue.  The wire goes to the battery light.  It is shown on the various wiring diagrams.  It would not typically have anything to do with the ignition switch.

Okay, sorry about that, just asked the exact question on my other thread. So take out the ignition switch variable.

What is the process of elimination on this wire? Get rid of the plug(has 3 female connectors in it) and run a complete new wire from the alternator to the instrument cluster? I cannot find any exact process on this particular vehicle. Not sure if it's the same on the newer TDI's.
I'll look at the Bentley but if anyone can give the cliff notes I'd appreciate it.

[ORCoaster]

Heron,  The exciter wire is not in the three prong harness on my 81.  It is all by itself and runs from the alternator to the back of the instrument panel.  So it seems easy to trace and if need be replace with mouse free one.  When you say the alternator checks out does that mean you took it to the auto parts place and the spun it up on their bench tester?  Or do you see a positive voltage charge on the battery when the car is running.

I like to use one of those clamp on Amp meters on the red wire coming into the battery to see if the amps are high or low when starting the car.  I also attach a meter across the battery and watch the voltage change as I rev it up.  I also have a voltage and amp gauge in the car, aftermarket, and can see that I am initially getting high voltages and amps after starting the car and then the amps drop to just a trickle but the voltage stays up near 13.5 or 13.9. 

Hope this helps. 

[Heron]

Heron,  The exciter wire is not in the three prong harness on my 81.  It is all by itself and runs from the alternator to the back of the instrument panel.  So it seems easy to trace and if need be replace with mouse free one.  When you say the alternator checks out does that mean you took it to the auto parts place and the spun it up on their bench tester?  Or do you see a positive voltage charge on the battery when the car is running.

I like to use one of those clamp on Amp meters on the red wire coming into the battery to see if the amps are high or low when starting the car.  I also attach a meter across the battery and watch the voltage change as I rev it up.  I also have a voltage and amp gauge in the car, aftermarket, and can see that I am initially getting high voltages and amps after starting the car and then the amps drop to just a trickle but the voltage stays up near 13.5 or 13.9. 

Hope this helps.

Interesting, I only have the 3 prong plug on the back of this Motorola...? There is no trace of a singular blue wire...hmm. I know no one has messed with this truck since it was parked in 93 and I was the last one to drive it. There were absolutely no issues with any lights staying on. This is definitely an 81 built in Westmoreland.

Yes, I had it bench tested. I can/will test it with my Solar meter once I get the starter figured out and can start it without grinding my flywheel up.

[erichvw]

Charging light staying lit even after appropriate rev level has been maintained. Battery brand new(and putting out proper CCA's) and alternator checks out. Plug at the alternator was cleaned and lubed with dielectric grease.

I've read in places about this exciter wire but I cannot find what I should do to remedy it. Or, is this even the issue?

There was a family of mice in this truck. I've found some wires chewed but have repaired anything obvious.

When the alternator is idle it should be the only source of ground to light up your battery light.  If you unplug the exciter wire from the alternator then you should have no battery light turn on. If battery light stays on while exciter wire is unplugged I would suspect a shorted exciter wire somewhere.


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[Heron]

Charging light staying lit even after appropriate rev level has been maintained. Battery brand new(and putting out proper CCA's) and alternator checks out. Plug at the alternator was cleaned and lubed with dielectric grease.

I've read in places about this exciter wire but I cannot find what I should do to remedy it. Or, is this even the issue?

There was a family of mice in this truck. I've found some wires chewed but have repaired anything obvious.

When the alternator is idle it should be the only source of ground to light up your battery light.  If you unplug the exciter wire from the alternator then you should have no battery light turn on. If battery light stays on while exciter wire is unplugged I would suspect a shorted exciter wire somewhere.


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This is crazy. Another member said he had an extra wire outside the the 3 wire plug. I don't. Should I eliminate the plug, take apart the wires and redo the connectors? From what I've read two wires are the hot wires to the battery and the other should be a ground(blue wire/exciter wire).. 

[erichvw]

Charging light staying lit even after appropriate rev level has been maintained. Battery brand new(and putting out proper CCA's) and alternator checks out. Plug at the alternator was cleaned and lubed with dielectric grease.

I've read in places about this exciter wire but I cannot find what I should do to remedy it. Or, is this even the issue?

There was a family of mice in this truck. I've found some wires chewed but have repaired anything obvious.

When the alternator is idle it should be the only source of ground to light up your battery light.  If you unplug the exciter wire from the alternator then you should have no battery light turn on. If battery light stays on while exciter wire is unplugged I would suspect a shorted exciter wire somewhere.


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This is crazy. Another member said he had an extra wire outside the the 3 wire plug. I don't. Should I eliminate the plug, take apart the wires and redo the connectors? From what I've read two wires are the hot wires to the battery and the other should be a ground(blue wire/exciter wire).. 

What happens when you unplug the electrical connector from the alternator?  Does your battery light stay off all the time?


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[Heron]

Charging light staying lit even after appropriate rev level has been maintained. Battery brand new(and putting out proper CCA's) and alternator checks out. Plug at the alternator was cleaned and lubed with dielectric grease.

I've read in places about this exciter wire but I cannot find what I should do to remedy it. Or, is this even the issue?

There was a family of mice in this truck. I've found some wires chewed but have repaired anything obvious.

When the alternator is idle it should be the only source of ground to light up your battery light.  If you unplug the exciter wire from the alternator then you should have no battery light turn on. If battery light stays on while exciter wire is unplugged I would suspect a shorted exciter wire somewhere.


Sent from my iPhone using Tapatalk

This is crazy. Another member said he had an extra wire outside the the 3 wire plug. I don't. Should I eliminate the plug, take apart the wires and redo the connectors? From what I've read two wires are the hot wires to the battery and the other should be a ground(blue wire/exciter wire).. 

What happens when you unplug the electrical connector from the alternator?  Does your battery light stay off all the time?


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I'll let you know as soon as I figure out my starter issue and can start the truck without screwing up my flywheel. TY

[fatmobile]

Since it has a 3-prong plug it's probably a MK1 we are talking about right?,.. maybe a non-AC MK2?
 Unplug it and measure the voltage at the blue plug with the ignition on but car not started,.. glow plugs not on.
 You can even ground the blue and see if the light goes out.
Possible the wire is broken or,...
take out the brushes and see how short they are. Short brushes was the cause of this on my car last week.

[Heron]

Since it has a 3-prong plug it's probably a MK1 we are talking about right?,.. maybe a non-AC MK2?
 Unplug it and measure the voltage at the blue plug with the ignition on but car not started,.. glow plugs not on.
 You can even ground the blue and see if the light goes out.
Possible the wire is broken or,...
take out the brushes and see how short they are. Short brushes was the cause of this on my car last week.

Got it solved. I believe it was a bad wire that didn't "look" bad. 

Thank you for your input!