Alternator excite wire question

[KevinB]

Does this wire give a constant positive 12+ volts to the alternator? Or is only suppose to do it during start up?

TIA, I'm trying to locate a wiring problem with my car and I think the excite wire is to blaim. Right now I have it hot wired to a key-on acc. source at the fuse box.

 

[turbofabricator]

It is routed through the dash "Hillary" light (idiot light )

 

[KevinB]

It is routed through the dash "Hillary" light (idiot light )

LOL. Is it a constact 12 volt though?

 

[2 QK 4 U]

I believe the exciter wire runs from the alternator directly to the battery.

What it does is send charge back to the battery. Keeping it charged.

The post on the back of the alternator is therefore Always hot.

This is where you get the power for many accesory items such as the fuel pump hot wire kit. FP hotwire does go to a fuse and relay which allows current to only flow with key on and utilize the factory relays as well.

 

[2 QK 4 U]

I think I misread your question.

Are you talking about the single skinny wire that has a connector terminal that plugs into the alternator or the fat one that routes under the engine and to the batt?

 

[KevinB]

I think I misread your question.

Are you talking about the single skinny wire that has a connector terminal that plugs into the alternator or the fat one that routes under the engine and to the batt?

Yeah, I'm talking about the skinny wire that plugs into the alt and goes to the volt light. I'm trying to figure out how it works.

 

[2 QK 4 U]

Yeah, I'm talking about the skinny wire that plugs into the alt and goes to the volt light. I'm trying to figure out how it works.

Ok that wire is not constantly hot.

 

[2 QK 4 U]

I just went out and tested mine.

That plugged wire is only hot key "on" or "running" condition.

My guess is that when the engine is running... and when the idiot light does not see the proper voltage it comes on.

 

[83ttypecooled]

no charge

Hi,
Turn the key on, engine off. Does the charge warning light come on? If not, check the small single wire, or as you call it, the exciter wire, for circuit continuity. With key on, engine off,you should be able to ground this wire and turn on the charge warning light(battery icon}.If the light does not illuminate, suspect a bad bulb in the instrument cluster. This can cause a no charge situation.If the light DOES come on,the alternator regulator is bad.Since you previously stated that you were jumpering this terminal to achieve charging,my guess is that the idiot light circuit is at fault. Good luck with your troubles...

 

[David65]

Does this wire give a constant positive 12+ volts to the alternator? Or is only suppose to do it during start up?

TIA, I'm trying to locate a wiring problem with my car and I think the excite wire is to blaim. Right now I have it hot wired to a key-on acc. source at the fuse box.

Don't connect the lamp (L) terminal of the regulator directly to +12V! That terminal is not meant to see +12V directly. There needs to be a lamp or a resistor between that and +12V. Read these threads for some info I posted recently.
http://www.turbobuick.com/forums/general-turbo-buick-tech/223864-low-voltage-quad-air-booster.html

http://www.turbobuick.com/forums/general-turbo-buick-tech/223941-help-w-alternator-basics.html
:smile:

 

[KevinB]

Thanks David. So the bulb acts like a resistor? What could I replace the bulb with? I am rewiring the car....do I supply the bulb with a normal switched 12 volts? From the diagram, it looks that way.

 

[David65]

Thanks David. So the bulb acts like a resistor? What could I replace the bulb with? I am rewiring the car....do I supply the bulb with a normal switched 12 volts? From the diagram, it looks that way.

Yeah, you can. You could also replace the dash light with a resistor, a couple hundred ohms in value maybe, and connect it to some switched +12V source under the hood. If your not handy with a soldering iron , one of these from Caspers might solve your problems.
https://www.casperselectronics.com/...creen=PROD&Product_Code=102032&Category_Code=

 

[Dewey]

Kevin, I just recently have been dealing with this problem. I couldn't get voltage to my alternator and so it wouldn't charge. I've checked everything from grounds to contacts on the circuit board on the back of the digital dash cluster. When you pull out the digital dash there's the vertical plug with all the copper tabs on it. The brown exciter wire to the alternator is the second one down on the left. The power feed to the volts light is the top tab on the right. You should have power to this tab with the key on. If you do then the problem is between there and the alternator. I called John at Casper's and he told me a test to run. Take a piece of wire and on one end attach a small bulb like a dashlight bulb and run the other end to the battery positive. On the other side of the bulb run a wire to the brown exciter wire behind the alternator. You 'll have to skin back a bit of the insulator. With this done, turn on the key. The bulb should light up. Once you start the car the bulb should go out. This means the alternator is working properly and the problem is definitely your exciter wire. If you've checked the power feed tab to the dash I mentioned earlier and it's good, then the problem is the digital dash itself. Then you need the part that David posted the link for. I ordered one yesterday.

 

[KevinB]

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