Charge indicator light - huh?
Put your feet up and settle in, this one has me a little baffled.
I need some help getting my charge indicator light (the "GEN" light) on my 69 GTO to act right.
Here's some background: The car originally had a Delco Remy 10DN alternator with external voltage regulator, as most did. However, that system didn's supply enough current to keep up with my system after adding those big honking twin electric cooling fans (30 amps each) so I converted to an internally regulated CS130 alternator that puts out 105 amps. Here's how I connected/converted it:
The CS130 has a main BATT connector for the output, plus a 4 pin connector that has terminals labelled S I/F L and P. "S" is for "sense" and it needs to "see" the alternator's output so the internal regulator has a reference to control alternator output. I/F is a connection to Field positive and normally isn't used. L is the connection for the charging indicator light. P is connected to the stator and is normally used as an input to a tachometer or engine hour meter (like on an airplane) - also not usually used in a car.
So, in the Beast I have the CS130 connected like this:
Batt goes to the main alternator output (fat wire that goes to the starter solenoid terminal - same as with the stock alternator). I put a short jumper from the Batt terminal to the S (sense) terminal on the alternator. The L terminal is connected to the black wire with white tracer in the original engine harness that goes back to the original external voltage regulator connector (one of the "middle" two terminals on the VR connector). At that connector, the brown wire on one end of the connector goes to the indicator light in the dash - eventually. When I converted to the CS130, I left the extrnal VR installed but just unplugged the connector and used a jumper wire to connect the brown wire to the black/white tracer wire which completed the circuit from the light to the L terminal on the alternator.
Everything was working fine. The light worked like it was supposed to ("on" with key on, engine off - "off" with engine running). Until a few days ago.
I was driving the car and the light came on. I checked the alternator output with a meter when I got home, and sure enough it was only making about 13.5 volts instead of the needed 14.4, so I replaced the alternator (under warranty) and verified the new one is making 14.4 volts output just like it's supposed to.
However, now the light isn't cooperating and I haven't been able to figure out why. It doesn't make sense.
Here are the symptoms I've identified so far.
* Engine running - light is on, brightly - this isn't right.
* Ignition on, engine off - light doesn't come on - or maybe it's on but very very faint. Sometimes it wil flash briefly, but doesn't stay lit. It acts the same way if I turn the switch to ACC - I don't think this is right.
* Completely remove the jumper at the VR connector - then if I turn the ignition on, or turn the switch to ACC, the light comes on and stays on - brightly - I don't think this is right.
* Ignition off, engine off, jumper disconnected - if I apply 12v to the brown wire at the VR connector, the light is on bright - I think this might be right?
My understanding of how the light circuit is -supposed- to work, is that with the ignition on, engine off, the path through the light to the L terminal ultimately goes to ground, completing the circuit, and turning on the light. When then alternator is charging however - alternator output voltage is feeding 'back' out the L terminal instead of going to ground so there's no current flow to turn the light on. I'm not 100% positive if that's how it really works or not. (Does it?)
With all that in mind, I'm at a loss to explain why it's doing what it's doing.
If there was an 'open' in the light circuit, why does it light when I remove the jumper or apply 12v to the brown wire at the VR connector?
Why does the light come on with the jumper removed (well, obviously it has a path to ground somehere 'after' the light but 'before' the connector - but then if that's the case why don't I have a dead short when I apply 12v to the connector?)
This is driving me nuts.