Candyman68

Ok so I've searched the forums with no help. I've done allot of troubleshooting.

​​​​​ When i turn the key to the ON position, the oil light and the gen light should illuminate.
So my GEN light will never come on.
I've replaced the bulbs with 194s, no light.
I've swapped the bulbs with the oil light, oil light comes on, no gen light.
​​​​​​I've taken the connector off the back and the solid brown wire has power with the key ON. when the key turns off, the power turns off.
The back of the gauge circuit looks perfect, ground copper is near mint. I've cleaned the pin connectors on the back of the gauge even though they looked good.
​​​​
​​Like i said, I've switched around the plastic bulb holders and the others light and the gen light doesn't.
Not sure where to go from here.
Let me know if you can think of anything else for me to try.
Thank you

joe_padavano

The GEN light gets 12v to one side of the bulb any time the key is on. The other side of the bulb is connected to the alternator. That wire is connected to ground in the regulator of the alternator is not making power (like when the engine is stopped) and gets 12v when the alternator is charging. When grounded the light comes on, with 12v on both sides the light goes off. If that wire is broken, the light won't come on. If that wire has 12v with the engine off, there's a problem in the regulator.

Oldsguy

Also, a visual inspection of the pin, printed circuit run, and pad for the bulb all LOOK good but it might be a good idea to ohm out from the end of the pin to the pad around the bulb holder for zero ohms. The light will not illuminate without that difference of potential even if the alternator is working correctly. But honestly, I agree with you Joe, I think it would be the regulator, there are more chances that a previous owner had messed with something under the hood than behind the dash (wiring) or the alternator is bad.

Candyman68

Hi Joe! Thanks for the reply and the explanation is great!
However, the wire has no power with the engine off. (You are talking about the connection plug wire that connects to the pins on the back of the gauge right?) It has power with the key switch ON, but the bulb does not light.

Candyman68

Ah ok, i was wondering how to actually check that circuit from the pin to the pad by the bulb.
I will add that to my list of things to check.

If that connector plug is getting power with the key on (and no power with the key off) is the regulator still a concern?
thank you for the reply!!

joe_padavano

Go back and read what I wrote. The brown wire should have +12V when the alternator is charging and should be connected to ground when the alternator is not charging. With the engine off, do you read zero ohms to ground?

Candyman68

So with the key off, to the brown gen wire, i get 0V but 22 Ohms.
Then i turn the key on to access (but not the engine on), i only get 4.43V (and no ohms).

So it's not getting enough volts?

joe_padavano

Again, the voltage with key on and engine NOT running is irrelevant. There should be 13.8V with the engine RUNNING and the alternator turning.

Candyman68

Hi Joe
Ok, so with the engine running, it shows only about 5.8v.
Thanks again for all your help on this.
I just found it strange that my GEN light never came on with the key, like the OIL light.
So obviously something isn't working right.

Just fyi, cig lighter shows 12V with the key off.
The OIL light shows 12V with the key in the access position

Rob

joe_padavano

So either the alternator or regulator are bad.

Candyman68

Ok i know the alternator works so on to the regulator
Thanks

joe_padavano

Keep in mind that it can also be the wires in between.

Candyman68

The regulator looks new.
The plug contacts look corroded.
Is there a way to get the wire contacts out so i can sand them to clean them?

Sugar Bear

I would try to clean them in place with an electrical contact cleaner, brush them with a small brass brush and put dielectric grease on the contacts vs. removing and sanding them. Sanding can accelerate future corrosion and removing them can break things.

Yes the terminals can be removed, each one has small tab that needs to be depressed and the terminal pulled backwards out of the black plastic connector while the tab is released.

joe_padavano

Pull the contacts out. Use a jeweler's screwdriver or a straightened paper clip to depress the lock tank on each terminal. Obviously do them one at a time so you don't mix them up. And "looks new" means nothing. Has the alternator been tested for output?

matt69olds

Unplug the regulator, ground the brown wire in the regulator plug. Turn on the ignition, the gen light should be on. Remove the ground wire, the light should go out. If so, the gen light and wiring in between is good. That leaves either defective regulator or alternator.

Candyman68

It was the regulator!
I ordered a new acdelco d663, took the cover off and it looked nothing like the installed one!
So i installed the new one and bingo! Light comes on like it should!
Here's a photo of the new one and the one that was installed.
Thanks Joe and all for your help!

droldsmorland

The one without the coils is a solid state new style VR. I've been running one in the Olds for years with zero trouble...knock on wood. Just put one in the 68 Vette.

Candyman68

Glad the solid state work for you.
It was the last thing i would have thought would fail.
I spent hours trouble shooting.
Mine failed!
No thank you.

Fun71

I’ve had both solid state and mechanical regulators fail.

I was able to repair the mechanical regulator 30 years ago and it’s still working.

I’m an electronics failure analyst and the solid state regulator is still in the tool box.

Koda

I am at the point to bring my H/O back to external regulator. Is there a modern Delco mechanical one sold now? I have a Chinese solid state one I can put on.

droldsmorland

I have a simple Alternator/Regulator test I can upload. It takes 5 mins to tell you if it's the alt or the reg.

Fun71

There was a recent post about regulators and the person had a picture of newly purchased mechanical regulator. It may take a bit of searching to find that post.

Another thing you can do is swap the cover to make the exterior of whatever you have look like an original.

Candyman68

I think i saw it on another post of you had posted it before
But sure, go ahead
Thanks

Candyman68

So the ac delco mechanical regulator did NOT work and did not solve the problem. It actually made the problem worse by not charging correctly as testing with the volt meter, and the gen light stayed on constantly. I'm told the new ac delcos are made in China as well. Not sure how to verify that.

So i decided to buy a new solid state one. After testing with the volt meter, everything works correctly EXCEPT the whole dummy light issue not turning on when the key is on.

If my alternator ever fails, I'm putting an internal regulator one in.
But as for now, "that's all folks"
Thanks for playing.

Vintage Chief

How to you know the Alternator works? Where are the measurements to confirm this?

Did you perform this test?

Is it me or does this thread appear an attempt to make Egg Foo Young from Chop Suey.

I haven't found anywhere where the voltage of the battery was measured and stated. It's just hard to follow this thread.

Plain & simple.
What is the exact voltage of the battery as measured w/ a meter when the engine is off no key in the ignition?
What is the exact voltage of the battery as measured w/ a meter when the engine is running at idle w/ all accessories in the off position?
What is the exact voltage of the battery as measured w/ a meter when the engine RPM is increased to ~2000RPM?

Candyman68

Hi NORM! See answers below:

Quote:
Originally Posted by joe_padavano
Again, the voltage with key on and engine NOT running is irrelevant. There should be 13.8V with the engine RUNNING and the alternator turning.
YES TESTED WITH ENGINE RUNNING 13.93V
Quote:
Originally Posted by Candyman68
Hi Joe
Ok, so with the engine running, it shows only about 5.8v. What does "it" refer to? The Alternator?
THIS WAS THE BROWN WIRE PLUG AT THE GAUGE READING, PROBLY IRRELEVANT
Thanks again for all your help on this.
I just found it strange that my GEN light never came on with the key, like the OIL light.
So obviously something isn't working right.

Just fyi, cig lighter shows 12V with the key off.
The OIL light shows 12V with the key in the access position

Rob
Quote:
Originally Posted by joe_padavano
So either the alternator or regulator are bad.
Quote:
Originally Posted by Candyman68
Ok i know the alternator works so on to the regulator Thanks
How to you know the Alternator works? Where are the measurements to confirm this?
VOLT TESTED ALT BATT POST AT 14V WHEN RUNNING

Quote:
Originally Posted by matt69olds
Unplug the regulator, ground the brown wire in the regulator plug. Turn on the ignition, the gen light should be on. Remove the ground wire, the light should go out. If so, the gen light and wiring in between is good. That leaves either defective regulator or alternator.
Did you perform this test?
YES. LIGHT NICE AND BRIGHT GROUNDED> LIGHT GOES OUT UNGROUNDED

Quote:
Originally Posted by Candyman68
It was the regulator! Evidently that is not true.
CORRECT EVEN WITH THE NEW SOLID STATE VR THE GEN LIGHT IS VERY DIMLY LIT WITH THE KEY ON
I ordered a new acdelco d663, took the cover off and it looked nothing like the installed one!
So i installed the new one and bingo! Light comes on like it should!
Here's a photo of the new one and the one that was installed.
Thanks Joe and all for your help!
Quote:
Originally Posted by Candyman68
So the ac delco mechanical regulator did NOT work and did not solve the problem. It actually made the problem worse by not charging correctly as testing with the volt meter, and the gen light stayed on constantly. I'm told the new ac delcos are made in China as well. Not sure how to verify that.

So i decided to buy a new solid state one. After testing with the volt meter, everything works correctly EXCEPT the whole dummy light issue not turning on when the key is on.

If my alternator ever fails, I'm putting an internal regulator one in.
But as for now, "that's all folks"
Thanks for playing.
Is it me or does this thread appear an attempt to make Egg Foo Young from Chop Suey.

I haven't found anywhere where the voltage of the battery was measured and stated. It's just hard to follow this thread.

Plain & simple.
What is the exact voltage of the battery as measured w/ a meter when the engine is off no key in the ignition?
12.54v
What is the exact voltage of the battery as measured w/ a meter when the engine is running at idle w/ all accessories in the off position?
13.93V
What is the exact voltage of the battery as measured w/ a meter when the engine RPM is increased to ~2000RPM?
13.93V

I THINK YOU DID HIT ON SOMETHING. WITH THAT BROWN VR PLUG WIRE GROUNDED SEPERATLY FROM THAT TEST, THE LIGHT IS SUPER BRIGHT AS IT SHOULD BE.
BUT WHEN I PLUG THE PLUG BACK INTO THE VR AND TURN THE KEY ON, ITS DIM.

__________________
Norm

Vintage Chief

Those numbers are marginal. 12.6VDC is a fully charged battery. At idle all accessories off: 13.93VDC is marginal & 13.8VDC is rock bottom ALT output. A properly functioning ALT should put out between 14.3VDC - 14.8VDC @ idle and as you increase the RPM the ALT output should increase (yours remains same w/ no increase).

TEST: Place a load on the charging circuit (ALT):

(1) Begin as you did in previous test - all accessories off. Keys out of IGN SW. What is voltage at battery?
(2) All accessories off, start engine & measure voltage at the battery (exactly as you did previously). What is voltage at battery at engine idle.
(3) I realize this is boring and is repetitive. As you increase the engine RPM to at least 2000 RPM (or above) is there any measured increase in voltage at the battery as RPM increases?

(4) Repeat #3 (above). At idle, turn on A/C, headlamps, dome lamp, courtesy lamps, etc. to place a load on the charging circuit. Measure voltage at the battery at idle with accessories on (placing a load on charging circuit). What is the measured voltage at idle at the battery?
(5) With car running (as per Step 4) increase engine RPM to a minimum of 2000 RPM (or greater). Measure voltage at battery as engine RPM increases. Does the voltage at the battery increase as RPM increases?

Candyman68

See answers above
Thank you!

Vintage Chief

Obviously, if this were easy someone would have suggested you need to change this or that and be done w/ it. Charging circuits are not simple to diagnose a specific issue especially from the armchair. Noteworthy to your issue is the fact you've gone from GEN warning lamp which is always on, replacement of the OEM mechanical VR w/ a new mechanical VR (which evidently made things worse & the GEN lamp always on), & finally replacement of mechanical VR w/ a solid state VR. You passed the test suggested by Matt (Post #16) implying the wiring is correct.

I think we're back to validating either ALT or VR is suspect (e.g. remove bad wiring from the equation). I still think the numbers you measured when testing ALT output are suspect (not optimal). We haven't discussed battery voltage discharge (drop) over a period of time & several other factors but I'd like to move on to further validating/diagnosing the ALT. There is one additional simple deep dive diagnostic you can perform on the ALT by yourself. You "could" drive the car to a parts store and have them test the ALT rectifier; however, this test is simple and honestly removes any chance (1) the parts store employee is performing the test correctly with the testing device; and, (2) the parts store testing device is actually working properly. I would want further confirmation the ALT doesn't have a leaking diode, a set of leaking diodes, etc. The diodes makeup what's referred to as the ALT rectifier - the ALT puts out AC (Alternating Current) but the car can only use DC (Direct Current). Albeit, this situation is "rectified" via placement of a rectifier (diodes) inside the ALT. The diode(s) operate as one-way check valves trapping alternating current (AC) so the ALT outputs only direct current (DC). There are many reasons diode(s) can fail - many reasons; and, it's quite possible even a brand new ALT has a bad diode(s); even more possibilities an older ALT has diode(s) which are beginning to fail (you could have AC current leaking into the charging circuitry) via one or more bad diodes or a ground issue contained w/in the ALT itself.

You appear someone quite capable of correctly performing diagnostic tests. With that said, I'd test for a bad/faulting ALT rectifier by testing the diode(s). Again, this is a very simple test. There exists one important caveat to this test - the ALT must be isolated from the charging circuit. You don't need to remove the ALT - the ALT must be isolated from the charging circuit. The best method is to remove the negative (-) battery terminal from the negative (-) battery post as the very first procedure and isolate the negative (-) battery terminal so it does not touch anything. Next, my preference is to remove ALL wiring from the ALT by disconnecting ALL wiring from the ALT. The point here (again) is to isolate the ALT from the charging circuit. Sitting at an armchair providing instructions isn't the same as watching someone following those same instructions - you get the point.

There are numerous videos on testing ALT diodes. I suggest you watch several before you perform the test until you gain an understanding of how to perform the test and the desired outcome(s) of the diodes. Again, it's a very simple test - just watch several videos and you'll knock this out in a heartbeat.

You got this!

BTW, it would be a good idea if you could tell us what ALT is on the car either via part number or via a picture/image. This will help members determine if you have an OEM ALT, a rebuilt ALT, modified ALT, etc. Obviously, don't assume we know what ALT is on the car and this "could" be important.

Review several videos to get the hang of this. The only caveat is to "isolate" the ALT from the charging circuit. Here are a couple, pretty simple - watch some until you get comfortable w/ it.

droldsmorland

As promised, grab a coffee:
Externally regulated charging system troubleshooting
(Olds 1968-71ish) Could apply from 62 to 67. The principal is the same.

Key:
alt = alternator
ck = check
reg = regulator
VOM = volt/ohm meter
F = field
R = reg
VDC = volts direct current or DC.
~ = approximately

Pre-Checks:
-Verify all battery, alt & reg connections are clean & tight.
-Ck the positive connection at the horn relay.
-The reg body needs a good ground.
-Battery passes a load test.
-Alt belt tension within specified deflection spec.
-Proper charging system should output 13.8 -14.4ish VDC.

Regulator terminal designations:
F term = field, blue wire from alt to reg
#2 term = white reg wire from alt to reg
#3 term = red or orange wire
#4 = purple wire

Alternator connector designations:
Large red wire = 12 VDC from the battery (from horn relay)
2 pronged connector on alt:
F = blue wire to the F term on reg
R = white (reg) wire to #2 on the reg



1. Key on engine static, check battery VDC at the alternator main stud. See battery VDC? No? Trace and repair. It originates from the horn relay on the fender.

2. Disconnect the 4 lead plug from the regulator and the 2-wire connector on back of alt. Ck continuity of the blue & white wires between the reg & alt. Open? Trace & repair.

3. Reinstall alt 2-wire connector, leave 4 lead reg connector disconnected. Engine static, key on. Verify battery voltage present at terminal #3 (the black cage retainer/connector on the reg is numbered F,2,3 4). There should be zero VDC on terms 2, 3, 4.

4. If VDC is present at term #2 on the reg or R on the alt you have a leaking diode in the bridge assy. Bench test alt. Fails...rebuild alt. This will cause battery drain and a warm static alternator with key off.

5. Key "ON" should have 12 VDC at term #4 (this VDC signal comes from the fuse panel to the idiot bulb). No output will induce a ground on one side of the bulb...illuminating the gen bulb.

6. No faults yet? Leave reg 4 wire connector disconnected from the reg, clear any loose wires from fan & belts.

7. Start engine.

-Connect VOM across the battery.

-Raise engine RPM ~ 1000-1200.

-Place jumper wire between the F and #3, (orange or red wire on the 4-wire reg connector). You should see VDC increase and hear alt working. If you hear a growl from the alt = bad diode or stator winding.

-Don’t leave jumper connected too long (don’t let it go above 15-16VDC).

-If you don't see the VDC rise above the battery VDC the alt is bad.

-If VDC rose quickly then dropped off the belts slipping.

8. On the 4-wire reg connector, connect VOM + to #2 white wire and momentarily jump F and #3. You should see 8-10 VDC. If not see this you have a bad diode or bad internal connection within the alt or reg...Solder joint? Open?

9. If all OK to this point, connect the reg harness back onto the reg. Make sure its seated 100%. Still not charging? Run a ground jumper from a known solid ground (or battery neg) to the reg metal body (not to the lid). Still not charging? Replace the reg.

Vettes are notorious for bad grounds at the regulator. Old cars are notorious for bad grounds EVERYWHERE.



In conclusion if you do not see the dummy light illuminate when it should the opposite side of the bulb has likely lost its ground in the ignition switch, wire harness or trace board on the rear of the gauge head. Or the bulb or sockets bad.

That circuit is initiated when the key is turned to start, bulb illuminates, sends VDC through the reg out the blue wire to excite the alt. When the key is released to run the signal circuit is interrupted and the bulb goes off and the alternator begins outputting.
If the alt isn't outputting the gen light will stay illuminated.

Hope this helps.
Steve

Candyman68

​​​​
First, i have learned a ton from going through all these exercises. I'm not an electrical type of guy but learning about how this system works has been eye opening and i love learning!

One correction, i started this thread originally because my GEN light would not come ON at all.
With everything I've done, it now comes on DIMLY but appropriately.
​​​
The alternator i was told when i bought the car last year that it has been rebuilt but kept on its original housing. However i don't know how old the rebuild is done he owned it since 94. Photo attached.

I did the isolation test and the diodes appear to work properly, photos attached. Red on case, black on post, volts flow. Just not sure if flowing 100%, my readings and the readings from the video didn't match up.

Black on case, red on post, no volts.

Vintage Chief

Sorry, right you are - thread started w/ GEN light would not come on (I was helping another member w/ the exact opposite). So....

You have a leaking diode (>.800 mV). Your measured rating is 1.047 V. The voltage drop range is 0.500 mV - 0.800 mV (for Silicone diodes). You are leaking AC current or (and this is most likely the issue), you have a ground short in the ALT causing the dim illumination of the ALT lamp w/ engine running. It (a diode) hasn't gone "pop" just quite "yet" but the rectifier bridge (consisting of usually a tri-pack of diodes) is beginning to fail - most likely shorting w/in the rectifier bridge.

Depending on the sensitivity of the automotive parts store equipment, they may or they may not be able to diagnose your faulting diode issue. Next step would be to drive the car to the parts store and have them perform a diode test. Note, sometimes the test equipment might not demonstrate a leaking diode or minor ground fault failure - much depends on equipment sensitivity & most of the test devices are generally an ALL or NONE fail scenario.

Replacing one of more internal ALT diodes is sorta complicated. Maybe go to a couple stores and have them test the diode rectifier set.

Vintage Chief

I should point out when I state you most likely have a ground short in the ALT a common theme is for a diode to overheat/breakdown causing the diode to ground out w/in the containment of the rectifier bridge.

stellar

Unplug the condenser from the regulator and see how the light works. seems you may have a bad one. If using the solid state reg, the condenser isn't needed. If using the mechanical regulator replace the condenser.

Fun71

Oh no! Silicone diodes means breast implants are silicon!!!!

Candyman68

Hi, i unplugged it and no difference, gen light still lit DIMLY with key on before starting.
Thank you for the suggestion. I'll leave it unplugged then.

Vintage Chief

Ha ha. That was funny. I did spell that incorrectly. My bad.

stellar

Everything has been covered pretty good. The only thing left that could cause a dim light is a bad ground to the regulator. I saw the pic of the reg bolted on, but the metal it is bolted to may have a bad ground. Try a jumper from the regulator base to the battery neg post and see if the light is any brighter. When the plug is in the reg the light won't be as bright as when the plug is out and the brown wire is grounded, but it shouldn't be dim,

stellar

Well there is silicon in silicone, so implants may stop current in one direction. I don't know. I once saw on tv torture of a guy by connecting jumper cables to another guys ***** trying to get information out of him. Maybe if he had implants he would have been able to resist.