E-Bodies.org Cuda Challenger Forum

So I finally got out in one of the cars last night and all seemed good, everything looked normal.  Cruising down the road Alt gauge was where is typically is on the charging side. Minute later look down and it is discharging??  Then as I'm looking at it . . . it bounces back to the charging side.  Everything is pretty new but it appears that I have a loose connection somewhere??  I checked everything on the alternator and nothing seems to be loose or corroded? 

So my question is . . . where else should I check?  Where else does the charging circuit run that could have a short?   :notsure:

First place I would look is the voltage regulator mount... tight & clean for a good ground.
  of course it can be any one of a multitude of connections issues. 

Quote from: Bullitt- on June 08, 2018, 07:22:32 AM
First place I would look is the voltage regulator mount... tight & clean for a good ground.
  of course it can be any one of a multitude of connections issues.

That is a place I did not think of . . .  :worship:

 :iagree:
Bad regulator ground or bad reg

Didn't have a chance to check that today but hope that is the cure!  Thanks guys!  This site is awesome! 

:worship:

So I have checked many things, cleaned many connections but today had the same issue . . . was going well and then, not charging again!  Strange thing I noticed is when it is not charging, my turn signals don't work??  Makes me wonder if my brake lights are working as well?  Now I am thinking it is a ground issue, so what ground would affect the charging system and the turn signals?  Someone please bring a meter to Carlisle if I don't get this figured out prior . . . mine is dead. 

:pullinghair:

What else is on when this happens?  Lights, Radio, AC, Heat?  When you are driving and turn on the lights what happens to the Alt gauge?

Quote from: Cuda Cody on July 09, 2018, 01:58:57 PM
What else is on when this happens?  Lights, Radio, AC, Heat?  When you are driving and turn on the lights what happens to the Alt gauge?

I'm gonna have to play with that . . . today was the first time I noticed that the turn signals didn't work.  Really not much else is running . . . I guess the electric fans could be running?   Radio is off, no AC in the car, 92* out so no heat, middle of the day so no lights . . .


Everything else is good, running good, shifting good . . . I'm afraid to shut it off and not have it start so limited driving until I get this figured out. 

Did you try swapping out the VR?

Quote from: 71-440 on July 09, 2018, 06:09:42 PM
Did you try swapping out the VR?

I have not but probably will . . Have a brand new one on the shelf.   :dunno:

Now I have another question, since I run with electric fans and a shaker hood, I feel that can cause a lot of heat in the engine compartment at times.   I know the fans don’t run all the time and the shaker contains alot of the heat, could the VR be over heating? (It is pretty new)   If I switch it out and it fixes the issue, should I put something on the VR to get it off the firewall so it gets more air behind it?  I know my 73 has a mount that pulls the VR off the firewall . . Thoughts? 

Quote from: Spikedog08 on July 09, 2018, 12:53:31 PM
So I have checked many things, cleaned many connections but today had the same issue . . . was going well and then, not charging again!  Strange thing I noticed is when it is not charging, my turn signals don't work??  Makes me wonder if my brake lights are working as well?  Now I am thinking it is a ground issue, so what ground would affect the charging system and the turn signals?  Someone please bring a meter to Carlisle if I don't get this figured out prior . . . mine is dead. 

:pullinghair:

The turn signals and brake lights not working at the same time as when the alternator stops charging? I think you may have a bad connection at the main splice of the dash harness behind the ammeter.  Not easy to get to, but it is a common point for the alternator output and the BAT side of the fuse block. The turn signal and brake fuses are there.  :thinking:

I don't know how heat would affect the VR  but I do know under hood temps on my car are pretty high. I have electric fans also.
I removed the block off plates on the scoops and the heat that comes out of them when at a stand still is pretty
amazing. I'm sure the small amount of air that gets in while cruising helps. :alan2cents:

Quote from: Spikedog08 on June 08, 2018, 07:05:08 AM
So I finally got out in one of the cars last night and all seemed good, everything looked normal.  Cruising down the road Alt gauge was where is typically is on the charging side. Minute later look down and it is discharging??  Then as I'm looking at it . . . it bounces back to the charging side.  Everything is pretty new but it appears that I have a loose connection somewhere??  I checked everything on the alternator and nothing seems to be loose or corroded? 

So my question is . . . where else should I check?  Where else does the charging circuit run that could have a short?   :notsure:

Might be the electric fan coming on and off? Maybe your alternator can't keep up with the electrical add ons? I ran into that issue with mine  when I ran a stock alternator.

  "Strange thing I noticed is when it is not charging, my turn signals don't work??  Makes me wonder if my brake lights are working as well?"
If the alternator won't keep up maybe there is not enough amperage to run the flasher?  :notsure:

Could it be everything is working fine and the gauge just lost contact for a bit?   :notsure:  If you are still running and driving it and the battery has not gone dead it doesn't sound like it's causing any problems?  You need to drive it more to get a baseline.   :alan2cents:

Electric fans pull a ton of current. A stock style 70's alternator isn't going to come close to keeping up at idle. The VR's get hot but they've been in that spot for a lot of years.

Are you running stock wiring ?   Or modified for the alternator lead thru the bulkhead connector...??    if stock that has always been a source of problem, doesnt take a lot of corrosion on the bulkhead connector to have an issue passing that much current thru the bulkhead connector...   That would be my guess if the VR is ok.   

Had same issue with mine for a long time. Definitely check grounding. Some of the VRs I purchased were even painted on underside face where they bolt to firewall. Scrape that off to get metal contact. If you are still wired up for the normal bulkhead connections. I would suspect that to be an issue. Especially with electric fans. At minimum they should be powered direct bypassing bulkhead and amp gauge. My issue ended up being low and erratic signal voltage. Iirc it is the blue wire. Its voltage should be real close to output voltage. I checked mine by getting baseline voltage from battery with car not running. Then check signal wire voltage. Mine registered over 1.5 volts lower. Ended up bypassing car wiring and ran new setup triggered with relays.

Good luck
Mike

With the battery disconnected see if the ammeter studs are loose they should not wiggle at all.  I bought rallye gauges on eBay when I went to install them my ammeter would indicate charging then not charging the studs were loose. Had to have it repaired. I did not check if I had signals or anything else but just about everything on inside of firewall goes through that connection.

Check connection number 18 at bulkhead

Your problem could be almost anywhere.   There are wiring diagrams available for free at http://www.mymopar.com/index.php?pid=27

Places i would check in order:

1) tight wires at the alternator
2) Make sure VR has good ground, and try replacing and see if it corrects problem.   
3) All of the wiring connections...  simplified...
A) power runs from alternator, there is a single disconnect behind distributor in the engine wiring harness..  from there
b)  into the bulkhead connector.   I believe post 18 this will be a heavy Black wire.   This will often with age get corrosion making a less than full contact...   Definitely remove the bulkhead connector and check both the male and female connectors for corrosion and clean.   c) From there it runs into a splice in the dash wiring that in turn feeds most of the factory systems.
   Not easy to check there but it could be a source of problem.   
4) From the dash harness splice it runs into the amp meter.   Again, not real easy to check, but, certainly if any of the nuts on the amp meter have come loose then intermittent results are possible.   
5) From the amp meter, a Red wire then back thru bulkhead connector i believe on post 16 (middle bulkhead connector).   This is a heavy red wire.   Again check that connector for corrosion.   Look for any signs of overheating !!!!!
6) On engine side the red wire in post 16 is supposed to be a fusible link which runs to the starter relay and then to battery.   

The voltage regulator pos input comes from a splice in the engine compartment wiring harness, and the field terminal wire runs thru engine connector in engine wiring harness..you will find behind distributor, and onto the field post on the alternator.   I believe that wire runs thru connecetor post 1. You might want to check for corrosion on it.   

Lastly, but unlikely is that the alternator itself has a diode or two that is beginning to fail.   

Hope you get lucky and the VR replacement fixes it...   Incidently, look carefully at the bulkhead connectors for signs of overheating...that is a heavy spot for failure...   

I know this is an old thread but I still have the same issue and I hope this winter I can get to the bottom of the problem.  Electricity is not my strong suit but I need to learn so I may ask a whole lot of questions and some may be (probably be)  stupid . . . warning in advance. 

I guess the first thing I should do is buy a good meter . . . I bought a cheap one last year and it has already crapped out.   Recommendations please? 

I took the car to a local auto shop and asked for help with this issue, after 4 days and $400, I was told 1 wire was not thick enough and was replaced somewhere by the battery  . . . waste of money.  I called another Mopar/auto shop and they didn't want to help . . kept putting me off and then said they would call me when they had an opening.  Been months now . . .

So this is a project I have planned this cold season . . . thanks for all the help in advance! 


First thing I will do is go through the list chargerdon posted above . . . and go from there.

Are you running a thick wire fan feed relay right off the battery? The sensors should turn on the relay.  Everything needs to be appropriately fused.

Quote from: 6pack on September 24, 2019, 09:34:34 AM
Are you running a thick wire fan feed relay right off the battery? The sensors should turn on the relay.  Everything needs to be appropriately fused.

Yeah I think it is mounted under the battery tray . . Believe it is all fused properly . . . Worked great for many years . . Then . . . Issues.  I know when the guys were looking at it in Carlisle . . It was discovered that from the alternator to the battery, somewhere I was losing 2 volts.  Something somewhere is draining or restricting the current flow . . .

$400 for nothing , I really am not charging enough !!
I could fly in & save you $$ except there is a glitch with that too  :Thud:
I would start with a simple voltage test , how many volts do you have at the battery & what does it drop too with everything on , it would  not surprise me if you need a higher output alt except that it was working ok before  :thinking:
Klein & Fluke are great meters but overpriced like Snap On , I look something with Quality leads as that is usually the first thing to fail GB & Sperry made decent mid cost meters

Quote from: Chryco Psycho on September 24, 2019, 11:03:37 AM

I would start with a simple voltage test , how many volts do you have at the battery & what does it drop too with everything on , it would  not surprise me if you need a higher output alt except that it was working ok before  :thinking:

Quote from: Brads70 on July 09, 2018, 08:02:50 PM

Quote from: Spikedog08 on June 08, 2018, 07:05:08 AM
So I finally got out in one of the cars last night and all seemed good, everything looked normal.  Cruising down the road Alt gauge was where is typically is on the charging side. Minute later look down and it is discharging??  Then as I'm looking at it . . . it bounces back to the charging side.  Everything is pretty new but it appears that I have a loose connection somewhere??  I checked everything on the alternator and nothing seems to be loose or corroded? 

So my question is . . . where else should I check?  Where else does the charging circuit run that could have a short?   :notsure:

Might be the electric fan coming on and off? Maybe your alternator can't keep up with the electrical add ons? I ran into that issue with mine  when I ran a stock alternator.

  "Strange thing I noticed is when it is not charging, my turn signals don't work??  Makes me wonder if my brake lights are working as well?"
If the alternator won't keep up maybe there is not enough amperage to run the flasher?  :notsure:

Mine worked"fine" to for awhile ( couple years) till I went on a long drive (Carlisle) and with all the electrical add on's and maybe the battery aging some , the stock alternator just wouldn't keep up.  Short 1/2 trips around town was fine ..... until it wasn't. at least 8 months a year the car was not in use and on a charger.  I'd say any electric cooling fan will draw more power than the stock system was designed to output.  your trying to get 20lbs of potatoes out of a 10 lbs sack?
Dave if you want I have a spare alternator I could mail you to try? Its one of those high output Quality power units but wired for 1 wire hookup

Thanks @Brads70 (https://forum.e-bodies.org/mlist/brads70_12) !  Very nice of you to offer.  For my $400 that I paid the last mechanic, he did tell me there is nothing wrong with the alternator as was also determined in Carlisle when the guys pulled it apart . . It is a serpentine system so that would be an issue as well.  I am gonna learn more about the electronics of these cars one way or another and I guess this is gonna be car electricity 101.  I'm going to Harbor Freight this week and buy a good meter.  Then someone will need to teach me what all the setting are for?  Fun Fun!  Garage is heated so have many plans for the cars! 

Hardtop just needs a lot of detailing and a few small things . . Convertible has this issue and needs some cleaning as well.  Plus I'm pulling the entire dash out for installation of a rallye cluster that I planned to do last year but never got to it.