Flickering Lights

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olddman

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Just got finished making repairs to wires going to the bulkhead connector in my 1965 Dart. What I thought would be an easy fix (!!) to flickering interior lights, and headlights that would dim at idle and brighten when rpms went up. When I pulled both connectors from the bulkhead three wires for the forward light harness only had a few strands attached to the Packard terminals. Plus all of the wires had been spliced into other wires that the previous owner had run. These other wires were about eight inches long and were spliced into wires coming out of the harness. This meant there were two splices using squeeze unions. Way too many unions! I replaced both bulkhead connector plug-ins and installed new correct color wires, Packard terminals, and used solder seal wire connectors to connect wires to wiring harness. Also pulled headlights and buckets to clean ground for head lights.

Also replaced the voltage regulator as it was bad.

Connected everything back up, started engine and I have the same problem as before. At idle, 800 rpm, the interior dome lights and dash lights are steady. At about 1,200 rpm the dome lights begin to flicker and when parking/dash lights are turned on flickering continues. Turn on the headlights the flickering stops. Headlights off flickering comes back until engine returns to idle.

Got out ammeter to check voltage and make some other checks but can't get it to work.

Need a little help!!
 
Measure the outside diameter of the pulley on the alternator and report back
 
Two changes fixed the flickering lights on my 66 Barracuda.:

1. Bought a headlight relay kit from @crackedback. Really quality stuff and if you need any assistance, he is willing to help.

2. I bought a solid state voltage regulator similar to the link. I keep my original in the trunk in case I need it.

Zero flickering now!

Oh, and I put in GE Nighthawk Halogen headlights.
 
66fyssh said:
Two changes fixed the flickering lights on my 66 Barracuda.:

1. Bought a headlight relay kit from @crackedback. Really quality stuff and if you need any assistance, he is willing to help.

2. I bought a solid state voltage regulator similar to the link. I keep my original in the trunk in case I need it.

Zero flickering now!

Oh, and I put in GE Nighthawk Halogen headlights.
Click to expand...
What solid state regulator did you use?
 
Couple comments. Is this "flickering" ---is it cycling up and down IE you hold the throttle at a set speed off idle, steady, do the lights "cycle" up/ down /up etc? Or are you referring to just dimming down at idle?
With all that you've done, you need to re-check for voltage drop to the regulator, and if that is OK then as suggested get a solid state regulator replacement.

If you add just one wire--since you have a squareback---you can convert to the 70/ later regulator
 
If the flickering is caused by a harness voltage drop, a "one wire" will not fix a thing. Further, in my opinion, "one wire" alternators CAN cause more trouble than they are worth. The sense wire is the charge wire, so any drop between there and the battery will cause problelms. The charge wire MUST be oversized depending on alternator output
 
I re-read your first post.
Im rethinking about the pulley dia. At 1200 rpm the alt should not produce a flicker. Have you had your charging system checked for bad diodes? Auto parts stores should be able to test for free.

Also as asked is it a flicker or a pluse?

To me a flicker is rapid, a pulse is slow,
 
Dana67Dart said:
I re-read your first post.
Im rethinking about the pulley dia. At 1200 rpm the alt should not produce a flicker. Have you had your charging system checked for bad diodes? Auto parts stores should be able to test for free.

Also as asked is it a flicker or a pluse?

To me a flicker is rapid, a pulse is slow,
Click to expand...

Various changes in brightness and voltage can also be caused by various problems in alternators, not the least of which is intermittent caused by bad brushes, loose windings which are rattling around and shorting, or problems with diodes.

I had my share of problems such as that on the old 70RR. The pulley ratio crank-to alternator was about 4:1, which means that at 5G engine speed, the alternator is trying to turn at 20K. I rattled two of them literally apart. One of them, the stator frame pins wore little notches in the lands in the case, and the rotor would contact/ rub on the stator. Yeh. I used to run the hell outta that thing

With 3.54 gear and the tires I ran, it was turning 3K at 70
 
It does sound like a varying voltage [ charging? ] issue. You need a ground cable from the body [ f'wall ] to the engine. Is there one?
 
Bewy said:
It does sound like a varying voltage [ charging? ] issue. You need a ground cable from the body [ f'wall ] to the engine. Is there one?
Click to expand...

Good thinking!!

I still have the original braided ground from head to firewall, but added 3 additional grounds for good measure. One from battery to core support, one from instrument panel to dash, and one from fuel sending unit to frame.
 
Additional information: 1. Using electronic regulator like Mopar came out with in 1969. Purchased from Quick Start. 2. When engine is at idle, about 800 rpm, the dome light, instrument lights, do not flicker. 3. When engine is brought up to about 1200 rpm the dome light, instrument lights begin to flicker (rapid bright to dim). 4. Turn on headlights lights stop flickering. Turn off headlights lights flicker. Head lights stay steady, do not increase in brightness or dim. 5. Have four (4) grounds from engine to frame and engine to bulkhead. 6. Have made sure that voltage regulator has a good ground. Even tried running ground from regulator to negative post on battery.
7. Did have charging system checked at parts store. Told that alternator was working but regulator was not. Thinking about taking alternator to different parts store and have checked.
8. Voltage meter needle jumps around like a kid on a pogo stick.
 
olddman said:
8. Voltage meter needle jumps around like a kid on a pogo stick
Click to expand...
Voltage meter as in external, it is reading around 12v or Ammeter in the dash showing charge to and from the battery.

Double check...

  1. You have square back alt with 2 field wires?
  2. You have checked the resistance of each field wire to the case of the alternator and both have infinite resistance (open - not grounded)
  3. You have a newer style electronic Voltage regulator with the V shaped connector.
  4. You have the newer style VR wired correctly?
 
olddman said:
Additional information: 1. Using electronic regulator like Mopar came out with in 1969. Purchased from Quick Start. 2. When engine is at idle, about 800 rpm, the dome light, instrument lights, do not flicker. 3. When engine is brought up to about 1200 rpm the dome light, instrument lights begin to flicker (rapid bright to dim). 4. Turn on headlights lights stop flickering. Turn off headlights lights flicker. Head lights stay steady, do not increase in brightness or dim. 5. Have four (4) grounds from engine to frame and engine to bulkhead. 6. Have made sure that voltage regulator has a good ground. Even tried running ground from regulator to negative post on battery.
7. Did have charging system checked at parts store. Told that alternator was working but regulator was not. Thinking about taking alternator to different parts store and have checked.
8. Voltage meter needle jumps around like a kid on a pogo stick.
Click to expand...

I see these possibilities in no special order:

1....Intermittent / bad connection 12V supply to VR and might be right at the VR connector
2....Problems as I mentioned earlier within the alternator
3.....Bad connection in the charge path
4.....Bad VR
5.....Intermittent / bad connection in field circuit

I'm not terribly sure that the average bench tester would show up the alternator problem

ONE THING you can do if you can "scare" it up: Get a big rheostat such as used to be in a typical VR/ generator/ alternator diagnostic meter for shop use. This allows external field control. You wire it in series, battery--rheostat-field-ground. This should show up intermittents in the alternator / charge path, IE eliminate the field circuit/ VR

If not, try "full fielding" the alternator direct from battery. Temporary wire field from battery--field-ground, WATCH RPM and voltage and just bring engine up and "hold" at 14-15.5 no more than 16V. Apply load, heater, lights, etc, and watch for flicker

If the problem is within alternator or charge wire, run a NEW (temporary) wire direct from alternator to battery and re-test for flicker/ variation
 
Can someone tell me where to buy a 2 1/2 inch diameter pulley for squareback alternator? Found a 2.6 one at Summit Racing.
 
2 guesses potentially wide of the mark.... :)

1) is the dash pod earthed, i had weird problems once because it wasn't, indicators not working and dash and dome light diming instead. once bolted back in, no problem.

2) The application of headlights puts load on the battery which in turn results in a load on the alternator. because the regulator sees it as a slight dip in battery voltage due to the lights being on (headlamps are quite power hungry). It keeps alternator ON.... when you switch them off the load disappears a bit, if you have a fully charged battery the regualator will flip-flop the alternator off on off on if the battery charge is on the knife edge between full and not so fully charged. if you have an ammeter in the dash that works, you will see it twicthing in time with the lights.

solid state regulator seems to do this more
i never had the problem with the old mechanical vibrator style

if so its just a function of your new modern battery, how charged the battery is and the way the modern regulator does its switching.
if you swictch on fan and wipers and it stops.... just like it does with headlights....well.

temperature also plays a part, might do it in the summer and not in the winter or vice versa .

i'd guess most are running around with a battery spec, much like this (or bigger).
they fit more into the space these days

Model 096, 278L x 175W x 190H, Wet, 12V, 75Ah, 700A
096 is Euro numbering for a flip top/top up battery that fits the tray with the right connectors and its designed to start a diesel or small truck motor 1970s to 1990s i.e not a battery designed for cars /SUV with 180 amp alternators and ECU charging control.

i would guess the one fitted originaly would be lower specification, installed at the lowest posible unit cost,designed to last the warranty period. On starting the car it will have slumped down below 12 volts and taken longer to get back up to 14 or so volts than anything we fit today.
i.e once car started, the alternator had a bit of work to do and the regulator would switch it ON and keep it ON at any rpm over idle for minutes rather than moments.. The system would not be left trying to make its mind up every 1/2 second. Starting the car would have had an appreciable effect on battery charge which we just don't see with a modern-ish High capcity battery and a denso starter.

really depends if its just a flicker or they are going off and on like your hazard lights...that would be a whole different thing.

Dave
 
Went out to the garage this afternoon to take a look at the wires running from alternator to VR and other wires as I had problems with wires in forward light harness. Thought I might find something wrong with the engine wiring harness.
Well this is what I found after unwrapping the wires:
1. Two wires from one field post on alternator going to VR post I.
2. One wire from other field post on alternator going to VR post F.
3. Yellow wire attached to field post on alternator connected to black wire that is then connected to green wire which then connects to VR post F.
4. Black wire attached to other field post on alternator and goes to VR post I. This wire is connected to blue wire and these two wires are then connected to white wire of VR plug. Blue wire goes to alternator, but was cut about six inches back from the alternator. Presume the black wire was run to replace the blue wire, but do not know why.
5. Squeeze type unions used to join wires. Plastic on one union was melted.
6. Alternator is a squareback. Both field terminals are insulated.
Shouldn't blue field wire be "Td" into the on side of the ignition switch? Was looking at a wiring diagram and green wire was going from one alternator field terminal straight to the VR F post. Blue wire went from other alternator field terminal to the VR I post but there was also a blue wire that was "Td" into this blue wire that went to ignition side of the ballast resistor.
I guess that I need to make this connection to the ballast resistor, or can/should I make connection somewhere else?
What harm was caused by this type of connection between alternator and VR?
 
If the new alternator is a revised squareback, they tend to draw more field current and may contribute to flickering at idle.
As far as a correct pulley. Get a good used one. Some (all?) of the new ones are too tight. You'll need access to a press to install it.

I tried todraw out your wiring as described and I couldn't.
Maybe this will help all of us.
On the voltage regulator:
I = Ignition Run
F = Field
Does this regulator have a triangular plug with 2 terminals?

On the alternator:
The threaded stud is power output.
There are two field brushes.
One is insulated and has a terminal
The other may be grounded, or it may have a male terminal. It sounds like yours has a terminal and is not be grounded.
Photos here: Identifying Chrysler Alternators (1960-1976)

Here's what it was and maybe that will help you figure out or at least explain what you see.
upload_2022-2-17_13-36-3.png


Typically Wire ID for late 60s.
A is Battery outputs (and recharge).
R is Alternator circuits. R6 is alternator output.
J is Ignition and engine.
J1 is often power to ignition switch
J2 is ignition run (includes power to voltage regulator)
J3 is ignition feed only when key is in start position.
Q is Accessory feeds
Q2 is switched accessory feed - (pretty much everything which requires key on other than ignition)
L is typically exterior Lighting
H is usually Horn.
 
Here's my best guess as to what you are trying to describe.
upload_2022-2-17_15-0-30.png


Blue could be the remnant of Ignition Run, J2A
Green could be remnant of the original Field wire, R3

J2A orignally connected to power at the ballast resistor.
If there is a second wire on an alternator's field terminal, then that may connect now to the Ignition Run circuit/

5. Squeeze type unions used to join wires. Plastic on one union was melted.
Sounds like it overheated due to poor connection or shorted.
 
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