Lights dimming and brightening

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chasb

chasb

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Can this be a bad alternator or voltage regulator?

Lights all brighten up when you rev up and dim back down when the car idles.

Is the voltage regulator built into the alternator ?

Don;t wnat the battery to overcharge and blow up.

Any help here? Thanks
 
The voltage regular is mounted on the firewall near the master cylinder. mechanical or solid state depending on what you are working on.
The first thing to do is have the altenater and battery tested.
All of the cars electrical goes through a fusible link at the firewall then the bulkhead connecter then the amp gauge then back to the wiring harness where about 5 wires are all bonded together near the inside of the firewall .
Any of that could be the problem. There are web pages that suggest an added wire under the hood to bypass all of that. Its a cure for the symptom and easier than hunting the actual weak link in the circuit.
If that doesn't cure it, the problem could be just a weak connection at the headlight switch or a weak ground somewhere.
 
RedFish said:
The voltage regular is mounted on the firewall near the master cylinder. mechanical or solid state depending on what you are working on.
The first thing to do is have the altenater and battery tested.
All of the cars electrical goes through a fusible link at the firewall then the bulkhead connecter then the amp gauge then back to the wiring harness where about 5 wires are all bonded together near the inside of the firewall .
Any of that could be the problem. There are web pages that suggest an added wire under the hood to bypass all of that. Its a cure for the symptom and easier than hunting the actual weak link in the circuit.
If that doesn't cure it, the problem could be just a weak connection at the headlight switch or a weak ground somewhere.
Click to expand...

C130 Chief said:
Bad grounds are where I'd start. Then clean firewall connector.
Click to expand...

1wild&crazyguy said:
Is this the old style regulator?
Click to expand...

DCP_3779.jpg
It looks like the old style alternator
 
All of that looks to correct and fresh to even consider adding wires or upgrading the charging system.
Check the battery ground to block. Check the engine ground to firewall. Check the headlight harness ground to radiater core support.
There is a replacement voltage regulater available that looks identical to that mechanical unit on the outside but solid state on the inside.
Your original round back altenater puts out only 36 or 42 amps which isn't enough if you add lots of aftermarket stuff like sterios, etc.. but was enough when the car was new and the headlights didn't blare with engine rpm then.
This may be a fun one to fix. Good luck
 
I do have an MSD ingnition in there now and I did put a hidden stereo system in. Other than that, all electrical is stock.

Any sources / part#'s for the solid state regulator.

Will a larger capacity alternator be the same physical size as the existing one ( I imagine it just has more wire wraps inside no?)

How would I test for the capacity of the exisintg alternator?


Sorry but I am electrically challenged. Thanks for all you help!
 
The look alike regulater previously mentioned is seen on ebay.
If you would like to update to a square back 60 amp altenater and later model solid state regulater we can show you how. Its very simple and that altenater will mount exactly as the round back. You have already added electrical equipment and may do so again so probably best to go this route.
Your decision.
 
RedFish said:
The look alike regulater previously mentioned is seen on ebay.
If you would like to update to a square back 60 amp altenater and later model solid state regulater we can show you how. Its very simple and that altenater will mount exactly as the round back. You have already added electrical equipment and may do so again so probably best to go this route.
Your decision.
Click to expand...

That would be great. That's what I like abut the forums. One big helpful family.

Direct me as to manufacrurers and part #'s for the equipment. If there are instructions etc, that would also be great. I'll pm you with my e-mail address.

Thanks Again

Chas
 
Looks like there is two regulators to me.... a solid state and electronic... see the little black box over the steering shaft?

EDIT:
Never mind I was seeing something different!

That is one good looking engine bay... bb too!!
 
I just switched over to the modern Alternator and Voltage regulator (2Wire) and it is like a different car. It even seems to idle better (Probably the MSD was sucking a lot of juice)
 
mullinax95 said:
Looks like there is two regulators to me.... a solid state and electronic... see the little black box over the steering shaft?

EDIT:
Never mind I was seeing something different!

That is one good looking engine bay... bb too!!
Click to expand...

Thanks. I work on it alot. (LOL)

RobbAdams said:
I just switched over to the modern Alternator and Voltage regulator (2Wire) and it is like a different car. It even seems to idle better (Probably the MSD was sucking a lot of juice)
Click to expand...

I think I'm going to take everyones advice and do that too.

THanks
 
There is still another option.
Like I said before there is a solid state regulater that lookks identiacal to your original ( black box ) . With it you could hang a 60 amp square back altenater on the engine and simply ground its second field terminal on it just like the factory did on the your 36 amp round back alt.
End result is more amps and more stable charging system with no complicated alterations required.
 
Hey Redfish, just a quick note, it's spelled "alternator", not "altenater". I do agree with your post too.
 
The next and real fix is to run your headlights directly from the battery source via a 30 amp relay (Two required). Use the old wiring to power the relays and you will still be able to switch from low to high beams.

Also keeps the high amperes out of the car and off that fragile headlight switch.


Here is a link to a great wiring diagram.


http://www.waywardgarage.com/tech/HeadlightRelayWiringDiagram.jpg

Good luck

Mop
 
I just upgraded my alternator last night with a later square back one using the same electronic regulator I had. I grounded the 2nd field terminal at the alternator. It now charges better, the headlights don't flicker and the output voltage at the alternator is more constant. Since the alternator was just lying around anyway this was a free upgrade so I tried it and it worked great!
 
The number one source of electrical issues on vehicles is inefficient grounding. The first place to start would be to make sure every ground is nice and clean bare metal to nice and clean bare metal. With all that nice looking underhood paint is there a ground coated with paint?

Once you are fairly sure all grounds are good there are several good electrical upgrades for A-body cars.

Check these links out:
http://www.madelectrical.com/electrical-tech.shtml
http://www.mymopar.com/charging.htm
http://www.4secondsflat.com/regulator_tech.html
http://www.mopar1.us/charge.html
http://www.imperialclub.com/Repair/Electrical/charging.htm

Or just do a search for Mopar voltage regulators, alternators or headlights.
 
chasb said:
Can this be a bad alternator or voltage regulator?

Lights all brighten up when you rev up and dim back down when the car idles.

Is the voltage regulator built into the alternator ?

Don;t wnat the battery to overcharge and blow up.

Any help here? Thanks
Click to expand...

Definitely NOT the voltage regulator.....it sounds like the alternator has weak output @ idle. I'd try a fresh higher output alternator. But before you do that, rev up your engine to 3000 RPM and check the current setup's voltage @ the battery. (all accessories off) That will tell you if your voltage regulator is bad......I think about 14.8 or so is around the highest you'd want. If your regulator allows the voltage to go higher than that, I'd say it's bad.
 
My 68 Charger had the same problem. I changed out everything (new voltage regulator, new wiring harness, checked all grounds and connections, etc., etc., etc). It was so annoying that I had to have my idle set faster just so I could see when I stopped at a stoplight. I never did track down the problem and it actually factored into my decison to sell the car. Looking back, the only thing I didn't change was the alternator. After my frustration, that's where I would start
 
1967DartGT said:
My 68 Charger had the same problem. I changed out everything (new voltage regulator, new wiring harness, checked all grounds and connections, etc., etc., etc). It was so annoying that I had to have my idle set faster just so I could see when I stopped at a stoplight. I never did track down the problem and it actually factored into my decison to sell the car. Looking back, the only thing I didn't change was the alternator. After my frustration, that's where I would start
Click to expand...

I went through the same senerio with our first 67 notch slant 6. The altenator upgrade didn't fix it.
Finally found the problem in the amp gauge itself. The entire electrical system was weak on that one not just the headlights.
My question for you is how much rust did the Charger have growing on it ?
I'm thinking almost none.
 
RedFish said:
I went through the same senerio with our first 67 notch slant 6. The altenator upgrade didn't fix it.
Finally found the problem in the amp gauge itself. The entire electrical system was weak on that one not just the headlights.
My question for you is how much rust did the Charger have growing on it ?
I'm thinking almost none.
Click to expand...

Nope, no rust issues at all. Are ya thinkin' my electrical problems actualy gave me free cathode rust protection?
 
I dont have a theory . I have noticed that differennces in electrical systems are reletive to rust rates.
 
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