Alternator whoas

[mattdg1]

Alright, I’m at my limits on a charging issue. Need recommendations. The car I bought had a Casper’s field fix on the car, along with voltage booster. The terminal on the field fix was reversed. Bad part on Casper’s unit which they warrantied even though 8-10 yrs old. Kudos to them. Their field fix powers the F terminal, whereas the factory powers the L terminal to tell the regulator to kick on. My Volt light in the dash is blown, so I need a secondary source. I’ve rewired the original weatherpacks to do just this. However, they have sent me a new one, the field fix from Casper’s (new one they warrantied), powering the F terminal of the alternator which still won’t make it kick on for charging.

Question 1: has anyone ever experienced this, and if so what did you do?

Question 2: if I have to run to the L terminal, what is the value of the resistor I need to add into the feed line from the wastegate solenoid to keep from damaging the regulator on the alternator.

I’ve spent hours, many hours, trying to chase this down. I’m sick and tired of it and just want the alternator to charge, and don’t want to damage the regulator. My car has the factory alternator and has been taken off and tested good. I first thought alternator wasn’t charging and simply wasn’t the case. It’s a 72K mile car and all that was done to alternator was have the bearing replaced since I had them tear it down just knowing it was bad, which wasn’t the case.

 

[KC87]

Just wondering why didn't you just replace the dash alt bulb? When you turn the ignition to on can you hear a very slight hum from the alt? Was it charging before?

 

[ScottHeidinger]

If you just ran a 12 volt wire to the alternator you probably blew the regulator in the alternator. You can use a 1k ohm resistor but if you have a good alternator then the field fix should work fine without replacing the dash light. The dash light provides the necessary resistance when connected in stock configuration to the L terminal. If you connected voltage to the L terminal without a bulb or resistor in line you probably damaged the regulator in the alternator so the alternator will need to be tested and probably replaced or rebuilt.


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[Speed Demon]

I had same problem. Took alternator to a rebuild shop and it tested good reinstalled and still wouldn't charge. Removed field fix no help (my dash light worked though). Installed my original (bad bearing) but it charged fine. Call shop and asked him what could be wrong and he determined he was testing it from one of the other terminals beside the one our car uses.

 

[asloan5]

I had same problem. Took alternator to a rebuild shop and it tested good reinstalled and still wouldn't charge. Removed field fix no help (my dash light worked though). Installed my original (bad bearing) but it charged fine. Call shop and asked him what could be wrong and he determined he was testing it from one of the other terminals beside the one our car uses.

I call bullshit on the shop. "used one of the other terminals"

 

[mattdg1]

I do plan on fixing it at the dash. I bought car and just got it running. The previous owner had put the Casper’s Volt Booster on it, and apparently the Alt Field Fox as well, although he had no idea that’s what it was. It just came with what he bought at Bowling Green yrs ago. He never had any charging issues.

I pulled the dash bezel this morning and found the bulb is working, but had a bad connection. Probably more work there to be done to make it reliable. Once I wiggled it enough to get a consistent connection, it was powering the exciter wire as it should, and the alternator was throwing 14.79 Volts. Therefore, I’m hoping the regulator is fine.

Previously, I had rewired the original Field Fix harness to power the L pin, pulling from the wastegate solenoid. I’m not sure if this offers any resistance or not to protect the regulator. I still have to check that.

However, the new Casper’s harness powers the F pin as well. I’ve verified from multiple discussions with Casper’s this should also excite the alternator. In my case, it isn’t. I’m wanting to have the Field Fix harness there as insurance. I guess at this point, I’m trying to learn why the F pin on my alternator isn’t recognizing the turn-on voltage through the field fix harness.

 

[ScottHeidinger]

My guess is the doesn’t have a factory alternator for a GN and previous owner had a field fix with connector for LT1 or whatever alternator that it is on the car. Just a guess.


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[Rosey1968]

Try a new alternator... be careful putting in not to scratch it so you can return if needed. I say this as I just had a low voltage issue that I was chasing and when I had the alternator test it tested fine... I could not find the issue and In frustration bought a new alternator and what do you know... it fixed the issue. In my opinion the new “fancy” alternator test machines have some flaws... like they suck. Just my 2 cents.

 

[ScottHeidinger]

Actually if I remember correctly the Buick doesn’t use the F terminal on the alternator with the field fix. It is the I terminal that gets 12v from the Casper harness not the F. It’s been years since I messed with this stuff. I switched mine to use a different alternator.


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[TurboTGuy]

I do plan on fixing it at the dash. I bought car and just got it running. The previous owner had put the Casper’s Volt Booster on it, and apparently the Alt Field Fox as well, although he had no idea that’s what it was. It just came with what he bought at Bowling Green yrs ago. He never had any charging issues.

I pulled the dash bezel this morning and found the bulb is working, but had a bad connection. Probably more work there to be done to make it reliable. Once I wiggled it enough to get a consistent connection, it was powering the exciter wire as it should, and the alternator was throwing 14.79 Volts. Therefore, I’m hoping the regulator is fine.

Previously, I had rewired the original Field Fix harness to power the L pin, pulling from the wastegate solenoid. I’m not sure if this offers any resistance or not to protect the regulator. I still have to check that.

However, the new Casper’s harness powers the F pin as well. I’ve verified from multiple discussions with Casper’s this should also excite the alternator. In my case, it isn’t. I’m wanting to have the Field Fix harness there as insurance. I guess at this point, I’m trying to learn why the F pin on my alternator isn’t recognizing the turn-on voltage through the field fix harness.

When you fix the dash light, Casper's sells a bulb that has a resistor so that if the bulb should blow again, the alternator will still charge.

I highly recommend that bulb!

 

[TurboWh1]

I have personally experienced all the above. Loose the bulb in the dash. It causes nothing but problems. Essentially it is the resistor in the circuit. In fact the wiring on that circuit is garbage altogether. Wire the factory alternator to function independently of the vehicle. That will ultimately solve your charging woas. Only down side is no idiot light. But we have scanmasters to confirm voltage.

 

[GNTtypeKid]

I just installed this new pigtail I got for $16 at AZ. Going to do some testing with it this weekend. Trying to fix some charging issues after an Impala SS alt swap.View attachment

 

[salvageV6]

Everyone needs to realize even with a bulb with a resistor in it, it won't charge at all if it's a bad connection at the dash flexible circuit board. The bulb rarely burns out but the connection goes bad a lot.

Both the bulb and the resistor need a good contact at the flexible circuit board to make the alternator charge.