[SBElsie]

For some reason now when I hook up my battery, even with the key off, the factory GEN light is illimunated. My voltage gauge is not reading anything too. When I turn the key to on the GEN light gets brighter. Is that some kind of feedback through my alternator? Nothing works in the car but that damn GEN light is on dim.

Everyone's opinion or suggestion is really appreciated! Help a broke college student out so I don't have to take the car somewhere.

 

[novaderrik]

unplug the alternator and see if that makes the light go off.
if it does go off, the problem is in the alternator.
if not, you got some diagnostic work ahead.

 

[SBElsie]

DUH, I can't believe I didn't think of that. I will try that tonight.

Any other suggestions?

 

[SBElsie]

Why wire? The plug with 2 wires (white and blue) or the positive lead back to the battery?

Thanks,

 

[Dean]

Why = which?

The positive lead back to the battery
Or ALL, it doesn't matter.

 

[1Fast7D]

Why wire? The plug with 2 wires (white and blue) or the positive lead back to the battery?

Thanks,

You mean which wire??? The plug with the 2 wires (white and blue).

 

[SBElsie]

Yes, sorry, I meant which wire.

I just tried that and it didn't work. I tried all three combinations with the alternator. Once without the positive (red wire) lead, once without the plug from the harness (white & blue wires) and once without either connected.

My generator light remained dim with all three combinations. The weakest area of my mechanics skills is electrical. Do I have a ground messed up? I don't see how this could have happened all of a sudden. Any suggestions are really appreciated!

 

[novaderrik]

if you still have the external regulator, unplug that.

 

[1Fast7D]

Yes, sorry, I meant which wire.

I just tried that and it didn't work. I tried all three combinations with the alternator. Once without the positive (red wire) lead, once without the plug from the harness (white & blue wires) and once without either connected.

My generator light remained dim with all three combinations.

That means the alternator isn't the problem. As Derrick said, unplug the external voltage regulator. The light should go out. Next, with the key off and the external voltage regulator unplugged, test the brown wire on the external voltage regulator plug for power or use a jumper and ground it. If the GEN lights, you have a wiring problem (backfeeding), if not the external voltage regulator is bad.

 

[SBElsie]

Three quick questions:

Which one is the external voltage regulator? Is that the one down behind the driver's headlights, or is that just the horn relay?

Where else could this be 'backfeeding'?

I noticed there is a Ground stud on the back of my alternator, I don't have anything hooked to it, should I?

Thanks for all your guys help so far, I want this done so I can cruise this weekend!

 

[novaderrik]

the voltage egulator is the 3" X 3" box right behind the driver's side headlight with a 4 wire flat plug going into the bottom of it. the brown wire does to the idiot light- somehow, current is getting into that wire, and you need to figure out why. if unplugging the regulator makes the problem go away, i'd suggest putting a newer style alternator in it and get rid of that regulator. it's an easy job, once you figure out what does what.
as for the "ground stud", i wouldn't worry about it. as long as you've got a good ground wire going to the block from the battery, the alternator is grounding fine..

sometimes, i wonder how we ever figured this stuff out without the internet. for things like this, i might have had a magazine article or something to guide me, but usually, i figured out what does what by jumping in and tearing things apart. sometimes, things got fixed fast. other times, the car would be down for a week over something stupid...

 

[1Fast7D]

Three quick questions:

Which one is the external voltage regulator? Is that the one down behind the driver's headlights, or is that just the horn relay?

First, determine which type of charging system you have, externally regulated (which is original for a 66) or internally regulated. You can tell the difference by looking at the orientation of the 2 small terminals on the alternator.

Where else could this be 'backfeeding'?

Generally caused by wiring something incorrectly.

I noticed there is a Ground stud on the back of my alternator, I don't have anything hooked to it, should I?

No. The alternator is bolted to the engine, which carries the ground.

 

[1Fast7D]

sometimes, i wonder how we ever figured this stuff out without the internet. for things like this, i might have had a magazine article or something to guide me, but usually, i figured out what does what by jumping in and tearing things apart. sometimes, things got fixed fast. other times, the car would be down for a week over something stupid...

Other times it never got fixed, and went to the next owner.

 

[SBElsie]

i'd suggest putting a newer style alternator in it and get rid of that regulator. it's an easy job, once you figure out what does what.

How do you get rid of the regulator? Or do you mean replace it? Thanks for the advice everyone, this website is so great!

 

[novaderrik]

Other times it never got fixed, and went to the next owner.

not too many of the cars i had in my youth ever made it to a next owner.. they never got smashed up cuz i'm a good driver and don't drive like a retard, but sometimes they never got put back together..

 

[1Fast7D]

i'd suggest putting a newer style alternator in it and get rid of that regulator. it's an easy job, once you figure out what does what.

How do you get rid of the regulator? Or do you mean replace it? Thanks for the advice everyone, this website is so great!

First determine what type of charging system you have.

First, determine which type of charging system you have, externally regulated (which is original for a 66) or internally regulated. You can tell the difference by looking at the orientation of the 2 small terminals on the alternator.

Opps, forgot to add the link, see this link on how to determine which type of charging system you have, w/pics http://www.chevelles.com/forums/showthread.php?t=105661

 

[SBElsie]

How do you test a voltage regulator? I'd rather not mess with changing it to internally regulated even if it is really easy.

I'm going to take my alternator and voltage regulator to the parts store today I think. Thanks everyone.

 

[SBElsie]

I put a new voltage regulator on the car, and had the alternator tested (it passed). I'm still having this problem of the idiot light being on dim when the key is off. I started my car to see if it would still run and to see if the electronics were ok (EFI) and it ran fine. HOWEVER, it would not shut off when I turned the key off! Pulling the negative lead off the battery didn't do anything so I had to pull the coil wire to kill it.

Was the car running off the alternator? How does that happen?

 

[david_396]

I had the same problem on my 67 years back. Change the reg. also. still had dim light. found a blown fuse. don't remember which one it was though??

 

[1Fast7D]

I put a new voltage regulator on the car, and had the alternator tested (it passed). I'm still having this problem of the idiot light being on dim when the key is off. I started my car to see if it would still run and to see if the electronics were ok (EFI) and it ran fine. HOWEVER, it would not shut off when I turned the key off! Pulling the negative lead off the battery didn't do anything so I had to pull the coil wire to kill it.

Was the car running off the alternator? How does that happen?

The GEN light works like this, with the car off and key on power is supplied to one side of the GEN bulb from the IGN switch, the ground side goes to the VR through the brown wire and is grounded at the VR. When the car is running, the ground is lost and power is applied to the ground side of the GEN bulb. With power on both sides of the GEN bulb it goes out. There is also a bypass wire incase the GEN bulb burns out (it is a resistance wire) that is wired in parallel with the GEN bulb. (in the dash harness)

First, (with the key off) you need to determine where the power is comming from that is lighting the GEN bulb, the IGN switch side or the VR side (new VR's can be bad). Do the test I posted earlier and post back.