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Discussion Starter #1
My gen light won't turn off in my 69 Camaro. I installed a SW Green line Amp gauge and it always reads in the negative side of the gauge. When I'm driving the car it reads just on the negative side, barely past zero on the gauge. but when I turn on the heater it drops to -30 on the Amp guage.
I installed a new alternator (I think a 55amp alt) and the battery and alternator checks good.
I'm almost tempted to remove the bulb from the Gen light. Any suggestions.
Should the amp gauge be reading that low when the heater is on? Maybe I need a bigger amp alternator.
 

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Just a suggestion here; My friend had a similiar problem and we found out that the wires that plug in the back of the alt. were reversed. Have you replaced your voltage regulator??
 

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I had a similar experience with my Chevelle ('69 SS396). After I replaced the alternator and voltage regulator, the dashboard alternator light would stay on. I would have to disconnect the battery for it to shut off. I ended-up putting the old (original) voltage regulator and capacitor back on and the problem went away....not sure what caused it or why it went away....
 

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Is your new Alternator stock with the external Voltage Regulator? If so you may need to adjust the old style mechanical Voltage Regulator or replace it with a modern solid state regulator such as an Wells AirTex unit.

If so then check the Voltage Regulator connection. Sounds like your not sending a full field signal to charge.

If you have gone to an non stock internal Alternator how did you shunt the four wires at the old Voltage Regulator position? A set of pictures of both the VR connection and rear of the new internal regulated Alternator.
 

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My alt tested good, the voltage reg was good but the excitor wire from the voltage reg to the alt was not telling the alt to start charging. You can drive on a strong fully charged battery for 50 miles or more before the engine won't start and run. The ignitor wire only gets used when the key is turning over the starter so it can be hard to trouble shoot if you don't know what to look for!

On a side note do you have wiring instructions for your sw amp gauge?
 

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Discussion Starter #6
My alternator is the factory 3 wire style.
I'll check and see if the alternator plug is in backwards.
Also the SW gauge is hooked up to the horn relay per the instructions.
 

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My alternator is the factory 3 wire style.
I'll check and see if the alternator plug is in backwards.
Also the SW gauge is hooked up to the horn relay per the instructions.
Check the wires, not the plug. The plug only inserts one way if I remember correctly. Purple wire on pass side and blue wire on drivers side.
 

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Hopefully, you have the ammeter hooked up correctly.
Remove the red wire from the horn relay buss bar going to the battery and insert with #8 gauge wire the ammeter. If you used the orange wire, fusible link for electrical system supply, you would be measuring the power consumed by the electrical system.

The choice is yours, you can even hook up the gauge to alt BATT stud to measure alt output. But generally, ammeter is hooked up to battery showing recharge/consumed power of the battery.

Ammeter should ahow negative value with alt off, show positive with alt on.
If not, reverse the leads on the back of the ammeter.

As suggested, GEN light staying on could be the two-wire plug is not plugged in good or a lead may have unlocked itself within the plug and not connected. Blue wire goes to F terminal and white wire to R terminal. Power on R terminal goes to VR #2 energizing field relay and exits VR #3 goes to GEN light turning off the GEN light.

I may have the wire colors wrong since I'm lookiking at a '68 manual and not a '69 manual.
 

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Also the SW gauge is hooked up to the horn relay per the instructions.
I wasn't doubting the way you hooked up the gauge when I asked about the instructions. Any chance you could scan them and e-mail them to me?

As far as the amp gauge goes I believe if you have a 55 amp alt you want a 60 amp scale on the gauge. You want the amp gauge to handle the output of the alt!

It sounds like your gauge is wired to measure draw, as you have seen when you run the engine and add accessories like the blower motor for the heater the draw goes up. The -30 you see is telling you the accessories are drawing 30 amps from the alt.
 

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Discussion Starter #10
I forgot to mention, the Gen light was on prior to the install of the Amp meter. Installed the Amp meter and it still comes on.
 

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I found this simple drawing online that I think will help...



The warning light has battery (+) present on the ignition side when the key is on. When the Alt is charging it puts battery (+) out on #1 which puts the light out. If the Alt isn't charging there is ground on #1 and the light is on. (when you put battery on both sides of a component like a bulb that is called a shunt)

#2 is the "excitor" wire that has battery (+) when the key is held on (starter running) but not when you release the key and the engine is running.

If the #1 and #2 wires are backwards you might be able to see the Alt light go out as you crank the starter over then come back on when you let off the key with the engine running.
 

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Test continuity of the blue wire from VR to Alternator and white wire from VR to Alternator. Still sounds like you have and have been having field issue.

Also what does the battery say voltage wise?
 

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Discussion Starter #13
I'll get back to my car on Tuesday and check things out.
I'll throw in another twist. Sometimes my oil light will flicker but will go out. I also have the SW mechanical oil gauge. Oil pressure reads fine.
 

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I found this simple drawing online that I think will help...



/
Notice anything missing here? No external voltage regulator! For illustration purposes I think this diagram works with internal regulator but I'm not sure the exciter wire comes from solenoid in most applications. If your running original alternator with external regulator ignore this diagram completely.

Jeff
 

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Jeff you are correct about the drawing, my heads still all plugged up from this crud I have and I was looking at the solenoid in that drawing as the voltage regulator. DOH! I just wanted ENP to see how the charge lamp worked...

I believe there is no excitor wire on an internal regulated alternator. Sorry for any confusion!
 

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Oh very good, an easy fix.
 
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