In the last week or two, I've been noticing that when pulling up to stop light (low RPM) my headlights dim slightly, as do the instrument panel lights.   I suspected that I should replace my voltage regulator, which I did today.  15 minute job.  No big deal.

However, when I started the car, at idle, the GEN light came on and stayed on until I pressed on the accelerator just a bit and the GEN light went off, and stayed off as I drove the car.  

As I approached a stop light, when the RMPs dropped off, the GEN light came on again.  When the light changed and I started to accelerate, the GEN light went off.  The cycle repeated itself.

So, because the wife doesn't know how look it takes to change the voltage regulator :-D, I drove over to the nearby auto parts store, bought a new alternator (I figured because why not..perhaps the old one was beginning to fail), and installed a new one.

When I started the car, the same thing with the GEN light continued:  idle = GEN light.  increasing the RPMs = NO GEN light.    And, it appears the headlights at low RPM dim even more than before I changed the Voltage Regulator and the alternator.   UGG!

I checked the ground on the voltage regulator and the ground appears to be solid.

The only thing I did not change in this circuit was what appears to be a variable resistor of some sort??? See below with the ARROW.  

Any thoughts about what might be going on????  Could it be that the new voltage regulator I installed is bad?


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Here it is with the new voltage regulator.   As I consider (obsess) this problem, it seems to me it either has to be this, the ground, or a bad voltage regulator, no?

Here’s a video of the problem.  Also, should ‘t the GEN light be on when the ignition key is in the ACC (eg radio only) position?

Thanks Mark.   I’ll give it a shot.

I put the old voltage regulator back on and the GEN light has gone off and I’m no longer having the problem.  Go figure.

i’m certain I need a new voltage regulator as the head lights are flickering and dimming slightly at low RPM.

I inspected the black ground wire from the alternator to the voltage regulator and it’s old and the plastic coating broken in several place.  I was considering running a new ground wire and trying out the new voltage regulator again. 
Of course, I could throw in the towel and take the car into my mechanic, but what’s the fun in that?



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