Possible Short between positive and negative, need help

Is the voltage regulator a part of the alternator or a separate external unit?

The voltage regulator is part of the alternator.  Both the alternators I have were rebuilt that way by two separate shops.

On a VW alternator equipt car it takes a small dash light to excite the regulator to actually make the alternator charge.  Not sure if applicable to GM alternator.

The thin blue wire goes to the dash indicator light and this MUST glow when you turn the ignition on. If this light blows the alternator will NOT charge the battery... it uses the tiny current in that circuit to excite the alternator into life when you start the engine.  http://www.vw-resource.com/replace_generator.html

Does battery drain over night or just not charge.

Have you cleaned and tightened your ground straps?

Wolfgang,

Yes, I'm very familiar with the exciter light.  I have it on my car and it always stays on at all RPM's.  I had it connected directly (with and without a light) and also in parallel with a resistor, and had the same result, not charging.  I also checked resistance on that wire (0.2 ohms) and tried connecting a direct 12V connection (as it runs off the ignition), also didn't work.  Also, for the GM alternators, the RPM's have to be above 1500 RPM's to start charging.  I can run the car well above that and still no charge.  The volt meter needle does move slightly towards 13V and the light momentarily dims, but still no charge.

The battery does NOT drain overnight and holds for weeks/months.  The only problem is with charging.

Bill,

Yes, I confirmed good (0.20 ohms) through the chassis.  Same deal on the positive from the battery to the starter solenoid, and to the alternator (.20 ohm or better continuity).  I cleaned and sanded the connectors as well.

61 light ( blue) this gets wired with the bulb    ground    to the 61 terminal on the alternator and the   positive tit   on the bulb goes to keyed 12v.

Isolate your charging problem by testing: 

Disconnect the 61 wire from the alternator to isolate the car's wiring... With the car running at 1400 plus RPM's use a test bulb - wire quickly tap  it from the alternator 61 terminal to the B+ and read your voltage. should be approx 13.8v

Also try a dedicated ground from the alternator case to a confirmed good ground....

Thanks Alan.  I already tried a dedicated ground wire from the alternator housing to the negative terminal on the battery.  I will try the 61 wire disconnect later today or in the week.

Vlad posted:

 If I take the battery out of the circuit (with the engine running) it goes down to 8.5v (output of the alternator). 

I was taught this was a very bad thing to do.  Removing the battery from the circuit allows spikes to travel to all electrical equipment and could burn out the diodes in the alternator.
But I'm no expert, just what I was always taught.
-=theron

I wanted to see what the alternator was outputing.  8.5V is way too low, so not sure if it's internal to the alternator or one of the positive shorting it down.

Careful!  Bob’s schematic is for an earlier, generator with external regulator.  What you have is a later alternator with the regulator built-in.  The schematic would be different.

Also, Something about this doesn’t hit me as a ground problem.

GM Delco alternators (with the internal voltage regulator) are different beasts than what most of us have on our Speedsters.  For one, they are a dual-exciter version.  There should be a big B+ post that should have a 10 ga. Wire going from there to the battery “+”.  When looking at the rear of the case and with the dual-wire connector straight up on the top, the B+ post should be on the back of the alternator somewhere around 10 o’clock.  

For that connector on the top (and still looking from the rear of the case), the right tab should have a 14 ga. Wire going directly to the B+ post (yes, it will be “hot” all the time), along with the 10 ga. going to the battery.  The Left terminal should have a white 14 ga. Wire going to the dash lamp.  If there is no wire from the right tab to B+ it won’t charge.  If those two wires on the top are exchanged, it won’t charge.  

I just found a visual to help you.  You might want to get this kit if you have the 1970s vintage 2-wire alternator.  It should help you keep charging down to around 800 rpm.

https://www.ebay.com/i/3710343...id%253D1454682923673

 Of course, if you have a single D+ tab on top, then I have to scratch my head a little harder, but let me know if you have a single or dual tab connector on top of the alternator.   Thanks.

BTW:  the correct alternator dash bulb for a GM alternator is an 1895 (if you wish to use that in your test bulb circuit).

An interesting side note about alternators not charging.  The tell-tale charging lamp in the dash is VERY important.  My alternator has only two wires on it: the always hot big honker that goes to the battery (B+), and the smaller one that goes to the dash light. The juice that makes the whole system work comes through that filament to the alternator.  So . . . a while back I was having some trouble with my tach, and ended up replacing it.  My "custom, hand-built" car had a veritable rats nest of wiring back there, and virtually no color coding on the wires.  And I screwed up. plugged the alternator bulb into the dash light wire and the dash light wire into the alternator tell-tale.  ergo, alternator would only charge if I had the dash lights on, and when I had the dash lights on the alternator light would come on.  I think we'd call this a false positive: light telling me charging was not happening, while in fact it was.  During the day with lights off,  we have a false negative: charge light is off telling me everything is fine, when it is not.  This drove me batty for a time, thinking the battery was failing, but then it would be fine, then it would be funky, depending how often I rode at night.  all very weird.  I did finally figure it out, and I can't tell you now how I troubleshot that.  Probably just decided that SOMETHING must have gotten switched while I was standing on my head under the dash hooking up wires.  So went back to Square One, and traced stuff out, found the switcheroo, fixed it, and then all was good.  Further: while most of what goes down here technically is guys who have been there and done that telling other guys what they learned.  I bet NOBODY has ever done what I just described.

And PS, as Gordo said: the old VW schematic of the VW and P generator, regulator lash up will do you no good at all with a modern alternator system.

Gordon Nichols posted:

Careful!  Bob’s schematic is for an earlier, generator with external regulator.  What you have is a later alternator with the regulator built-in.  The schematic would be different.

Also, Something about this doesn’t hit me as a ground problem.

GM Delco alternators (with the internal voltage regulator) are different beasts than what most of us have on our Speedsters.  For one, they are a dual-exciter version.  There should be a big B+ post that should have a 10 ga. Wire going from there to the battery “+”.  When looking at the rear of the case and with the dual-wire connector straight up on the top, the B+ post should be on the back of the alternator somewhere around 10 o’clock.  

For that connector on the top (and still looking from the rear of the case), the right tab should have a 14 ga. Wire going directly to the B+ post (yes, it will be “hot” all the time), along with the 10 ga. going to the battery.  The Left terminal should have a white 14 ga. Wire going to the dash lamp.  If there is no wire from the right tab to B+ it won’t charge.  If those two wires on the top are exchanged, it won’t charge.  

I just found a visual to help you.  You might want to get this kit if you have the 1970s vintage 2-wire alternator.  It should help you keep charging down to around 800 rpm.

https://www.ebay.com/i/3710343...id%253D1454682923673

 Of course, if you have a single D+ tab on top, then I have to scratch my head a little harder, but let me know if you have a single or dual tab connector on top of the alternator.   Thanks.

BTW:  the correct alternator dash bulb for a GM alternator is an 1895 (if you wish to use that in your test bulb circuit).

El Frazoo posted:

And PS, as Gordo said: the old VW schematic of the VW and P generator, regulator lash up will do you no good at all with a modern alternator system.

Sorry about that. Deleted the post to avoid confusion. Maybe I'll find the right schematic to post this time:

How's this one? If this one is wrong I'll just give up trying to help. LOL

Suggestion remains the same. Check the amount of current going in to and coming out of each point in the charging system and see where the problem rests.

Gordon,

My alternator is in fact like the one in the link you provided:

https://www.ebay.com/i/3710343...id%253D1454682923673

I have the D+ for the light and a B+ for the right terminal that T's to the large gauge connector at the 10 o'clock position.  I tried swapping the two smaller gauge wires before and there was nothing either way.  I vaguely remember disconnecting one or both before (forgot what sequence) and getting the alternator to work, but I have since not been able to repeat it.

One additional thing to note; does the dash bulb for a GM alternator need to be an 1895.  I currently have an LED light with a 10 ohm resister in parallel like the schematic below.  

http://www.easyhomeview.com/al...icator-lamp-battery/

I was worried about the LED so I swapped it out with a lightbulb, but still it would not charge.  I even eliminated the lightbulb/LED all together, and had the wire go straight to the ignition and still it wouldn't charge.

As I mentioned; the only time I can get the alternator to charge is either on the test bench or if I hook up a separate battery external to the car and it goes up to 14.5.  I really think it's in my car wiring.

I was worried about the LED so I swapped it out with a lightbulb, but still it would not charge.  I even eliminated the lightbulb/LED all together, and had the wire go straight to the ignition and still it wouldn't charge.

Delco Alternators are fussy buggers.  When they work, they're great, but when they get fussy they can drive you nuts.  First, I would get an 1895 bulb (which is pretty common as a dash "ALT" light bulb for most of GM) along with a bulb socket with pigtails and make a test light out of it, then, with the normal dash light wire removed at the alternator, run your test light between the D+ and B+ terminals and see if that makes it happy.  I'm not a fan of the LED and resistor, simply because I don't know what the resulting combined resistance will be (would have to measure it) and how that might compare to the correct bulb resistance.  Also, I'm not sure (never tried) if it would charge with the dash bulb wire connected directly to 12Volts - it's looking for a sense condition - it wants to see a range of voltage defined by the bulb resistance.  

On the other wire at the small connector, where does it go?  Does it go directly to the B+ (that would be about 12" long at most) or does it go off into the wiring harness "Never Land" to hopefully connect to the B+ somewhere else?  If THAT is the case, I would try a shorter wire from Top right to the B+.  In the end, it wants to see what is shown in your Easyhomeview diagram - Give it that and it should work.

As I mentioned; the only time I can get the alternator to charge is either on the test bench or if I hook up a separate battery external to the car and it goes up to 14.5.  I really think it's in my car wiring.

WHAT?!?!?!?  Is that jumpered to what's in there so both batteries are in parallel or do you disconnect the car battery and use jumpers from the internal cables to the external battery so that it's isolated?  What happens if you swap the battery in the car with a new one?  Maybe the battery in there now simply won't take a charge (internal plates crudded up - $#!+ happens).  That yellow highlighted sentence is a BIG DEAL and, I think, the key to the problem.

You know......As an OCD person, this is gonna bug me all day, but we'll get it charging yet.

So my B+ to the other connector is very short 4" or so, and is 10 gauge.  The short wire is crimped to the lug going to B+.  I also checked resistance, and its good (.15 ohms). 

I actually just ordered that harness kit: https://www.ebay.com/i/3710343...id%253D1454682923673 because it includes a diode to help charge at even lower RPM, and I was thinking about replacing my harness in any case.  I'm wondering if there may be a diode in that crimp (in my current set up) that may be installed backwards.  I may run a second wire from the B+ to exciter connector at the top just to check.

The places I took my Alternators to for testing were O'reilly because they were free tests.  I'm also thinking about taking them to a specialty shop like: http://www.autolectrics.net/   as they specialize in this stuff.  It may be that under load the alternator can't deliver.

As for the battery, it is literally 4 months old and is a good battery.  I didn't run the second battery in parallel.  What I did was disconnect the B+, D+, and exciter wire from the alternator and connected it stand alone to the new battery.  I was basically using the car to turn the alternator while running, and connected everything to the second battery.  The only common thing I connected was chassis ground.

One other thing to note while I was messing around with the headlight switch; the rheostat/pot was cracked for controlling the dimmer, and was affecting my highbeam/low beam due to a possible short.  I have a replacement on order.  I did take it out of the system all together, and still no charging, so unfortunately that wasn't it.  

I'm hoping that if I redo the wiring and put in a correct bulb, that will do the trick.  If not, I'll have to take it to a shop and spend some $$$.

When you get done with this you'll know more than the O'Reilly guys ever will. 

Heck, you could get a job with the Autolectrics guys!  Those guys are good to know - tell them everything you've tried so far and see what they suggest.  They'll certainly know Delco Alts. way better than me.

And, yes, you ALWAYS want to test an alternator under load.  They have big, honkin' resistors to apply as the load.  They get pretty hot under test, too!  

Vlad posted:

 ...while I was messing around with the headlight switch; the rheostat/pot was cracked for controlling the dimmer, and was affecting my highbeam/low beam due to a possible short.  I have a replacement on order.  I did take it out of the system all together, and still no charging, so unfortunately that wasn't it...

Hey, it's Sacto 'just guessing' Mitch here.

I have no idea if this applies to the wiring in your Corvair, but it's something to consider.

On the VW, a terminal on the headlight switch was used as a common point to feed 12V battery power to other circuits in the car that have nothing to do with the headlights. A wire brought 12V from the battery to the terminal, and wires for those other circuits were also led to the same terminal.

So, if you pull all the wires off the headlight switch, you could be disrupting other circuits on the car. It would help to examine the wires you pulled off the switch and confirm where they lead. Some of them may need to be attached to each other without being attached to the switch.

True, but the car started fine, just not charging as usual.  I'm sure I'll get to the bottom of it eventually. 

Hey, it's Sacto 'poor reading comprehension' Mitch here.

Just reread your original post and see that you don't have a Corvair, but a CMC with a Corvair motor (and a Corvair alternator).

So, it sounds like Gordon is on track and the problem is most likely getting the simple dashboard light wired up correctly to the not-so-simple tickler circuit on your alternator.

The wonky headlight switch can cause various kinds of pain until sorted, but it's probably not related to this charging issue.

Are we sure there are no Lucas components here?  If there were, that could explain a lot.  ;-)  I wish I could help here, but I can't, other than to say it sounds like a wire issue.  Hooked up independently w another battery you say all seems jake. Have you tried to put that second battery that you use on the bench into the car and see if it works any differently using the car's wires?  That would rule out for sure your primary battery as any source of issue.  Maddening.

Funny story- the headlight switch on my wife's VW Cabriolet welded itself off on a trip up to the lake ( no amount of pressure would flip the rocker "on"). The next morning, as my brother and I were tearing apart the dash to figure out what's wrong, he casually commented that VW must be buying electrical parts from Lucas. You can imagine our surprise (and laughter!) when I read the name on the back of the housing!

Yeah, and the British Rover "Sterling" that I pulled my fuse/relay panel from had a lot of.....  BOSCH!  And most other of what was underneath was an Acura!  That was one schizophrenic automobile.  I'm glad I saved the fuse/relay panel from ignominy.  

********************

I would still swap the batteries in the car and see what happens.  That charging of the second battery outside of the car bugs me.

I bought two, brand-new, 12 Volt "Wicked Big Heavy Duty" batteries from Carquest for my diesel truck, only to have slow crank condition all the time.  Then had an automotive electrical shop do a stress test on them both and found one had a weak cell.

While I also believe it is a wiring issue, it only takes 5 minutes to swap them and be amazed...   Or not.

Gordon, if you'd like an evening's entertainment, I dug up this schematic supposedly from a '65 Corvair - the car Vlad's alternator would have originally been wired into.

It's kind of a mess to follow - but it looks like the wire from the voltage regulator to the dash light (which would normally supply a ground to the light) is also connected to a pin on the ignition switch.  I think in old VW's, it's the OTHER side of the dash light that is usually connected to the ignition switch.

If you can make sense of this, you're a better geek than I am.

(The JPEG may be hard to read - a higher-res PDF is also attached)

The second battery I hooked up was a motorcycle battery, so I don’t think I can hook it up stand alone, unless I use the primary battery to jump start the car.  

I’m currently just waiting on the new headlight switch and also the alternator harness with the diode.  I’ll let you know how it goes after I install the items next week.

One more thing I thought about.  Can my distributor coil have a small short to ground? I  noticed when I was hooking up the positive there was a lot of sparks. The bracket holding the coil is bolted straight to the engine block.  I may try isolating it.  I have the pointless ignition with the flame thrower brand coil.

You may have a hair line coil crack or a nicked - bare  wire

So it doesn't look like a crack in the coil.  I hooked up a separate battery to the coil, and still no charge.  I received the harness with the diode and temporary installed that, which also didn't help.  I took my car to autolectic and they tested my spare alternator under a 45amp load, which tested fine.  The next step is to put my spare back in and test the original (supposedly rebuilt) alternator on the bench.  He also confirmed there was no output from the original alternator on my car, but I'm still suspicious of a potential short in my wiring harness.  He did hook up an ammeter and saw only 15amp draw while the engine was running.

Next step is to hook up a the spare alternator again and permanently install the new harness: https://www.ebay.com/i/3710343...id%253D1454682923673.

Still doesn't explain why the current alternator works with a separate external battery.  If the spare alternator doesn't work after install, I'll have to suspect it's the harness

Well.....I'm happy to report I'm now getting a solid 14.5V charge.  I ended up taking the spare alternator to a shop and verifying that it works under load.  They also tested my alternator in the car and confirmed it was NOT working.  I either screwed it up during troubleshooting or it never worked to begin with after the rebuild.  What I think happened is I had poor grounding.  When I installed the spare back in, it worked like a charm.  Now I need to go back to the guy who rebuilt my original alternator and have him fix it AND test it in front of me.  What a head ache, but I'm happy I got it working in the end.

Thank you all who helped with advice, I'm looking forward to a meet this summer!!!

[URL=http://s607.photobucket.com/user/fraktv/media/1956%20Speedster/IMG_1441.jpg.html][IMG]http://i607.photobucket.com/al...eedster/IMG_1441.jpg[/IMG][/URL]

Glad you sorted it out, Vlad.

I replaced a faulty voltage regulator with a new one that charges but has a no good charge light circuit, so I'll be swapping that soon myself.

That's great news, Vlad!  @Vlad

I was taught like Theron "never" disconnect the battery in an alternator equipped vehicle when it's running.  With a generator it isn't a problem - but it quickly zaps diodes in alternators.  Along with that warning was to never jump another car using a new car with all its electronics (ECU, EFI, etc).  Not to mention that hydrogen gas from the battery that can explode covering you and car with nasty sulfuric acid.

Same guy said "don't poke a sleeping bear" or "pee into the wind".