Headlights seem to oscillate

[Scoopy G]

Greeting fellas,

I had the Mighty Chrysler out this evening, and on the return trip I noticed the headlights and dash lights seemed to randomly go brighter or dimmer. Both the dash lights and headlights did this together, not independently.
It seemed to be about maybe 30 seconds to a minute between each dimming or brightening, and I would estimate the difference between them was maybe about 15%-20% in magnitude. Any ideas what could cause this?

 

[Davea Lux]

Greeting fellas,

I had the Mighty Chrysler out this evening, and on the return trip I noticed the headlights and dash lights seemed to randomly go brighter or dimmer. Both the dash lights and headlights did this together, not independently.
It seemed to be about maybe 30 seconds to a minute between each dimming or brightening, and I would estimate the difference between them was maybe about 15%-20% in magnitude. Any ideas what could cause this?

If you have a '69 or older Chrysler, it will have a mechanical voltage regulator, some brightening and dimming is normal in short intervals. You could have a regulator that is sticking and that is lengthening the cycle. Other possibility a an intermittent short someplace that is drawing down the voltage and causing the dimming. On the open road, your battery is probably fully charged, and the regulator is cycling. I would be inclined to replace the mechanical regulator with an electronic one and see if the problem goes away. You should also check the harness for shorts and be sure all connections are tight and the battery cables are tight as well if the problem persists.

Dave

 

[cbarge]

Im with Dave and go with an electronic voltage regulator.
Autozone sells a plug n play # VR706.
To totally get rid of the headlight dimming, I recommend installing a headlight harness with relays.
I use the Putco harness that includes two relays.
230004HW
It plugs n plays no hacking of any original wiring.
This harness also takes away the load from the headlight switch and foot dimmer switch.

Hope this helps.

 

[OKDart]

I had that happen on a 1970 Dodge Charger about 15 years ago. Never found the cause, but it went away once I did the headlight relay upgrade.

 

[CBODY67]

I'd wonder how long it's been since the car was last driven? Batteries tend to lose a bit of power when not used, although less with the newer ones than in the past. End result is that more-than-normal "charge" is happening (a bit brighter lights) than normal, which the main voltage regulator is modulating, normally. The "dim" could actually be the normal level rather than otherwise, posssible. The fully-transistorized main voltage regulator should keep things more constant, voltate-wise, then the OEM points-type unit. Of course, battery terminal connections at the battery posts can hide a thin layer of corrosion in that gap, by observation, which ALSO puts more electrical resistance into that circuit, which can decrease ultimate charging system performance. Part of the dianosis of this issue should probably include a mechanical cleaning of those contact surfaces.

The OTHER voltage regulator, the instrument cluster's "voltaage limiter", located on/near the cluster itself, might also be having some voltage cycles, too. The earlier units were mechanical, with a solid-state version being used from somewhere in the earlier 1980s, iirc. The later ones are a bolt-in replacement, I believe, and are available from several online sources.

In this case, starting with the underhood, main, voltage regulator replacement would be the easiest place to start. Plus the cleaning of the battery cable connections.

Depending upon how long it's been since the car was last run/driven, with normal running, it might take well over an hour's drive-time to get the battery back to close to full-rated charge. No "round the block" sort of thing! This longer drive-time will also alllow ALL of the vehicle's fluids to reach their normal operating temperature and get most, if not all, of accumulated/residual condensate cooked out of them, which is good. For example, once the engine coolant tamp gets to normal, it can take another 10 miles of 45mph+ driving for the engine oil to reach the same temperature in 70 degree F weather. Similar with atf. Cooler temps will lengthen the time for this to happen.

The battery state-of-charge isssues might include the use of "battery tenders" for "rest times" and the definite need of a good. quality, self-regulating portable battery charger, for good measure. Even one of the iPhone-sized jump boxes could be good to have in that arsenal, too!

Several dynamics in your situation, by observation.

Enjoy!
CBODY67

 

[Scoopy G]

Thank you gentlemen. I'll swap the regulator out today, and see about procuring the harness. Otherwise the battery is clean and fully charged.

I was aware that the harness would take the load off the headlight switch, as I had the switch rebuilt by Devin Duke last year, and he he made me aware of this, but I haven't done it yet.

So thanks again for the help, I appreciate it.

 

[Scoopy G]

Im with Dave and go with an electronic voltage regulator.
Autozone sells a plug n play # VR706.
To totally get rid of the headlight dimming, I recommend installing a headlight harness with relays.
I use the Putco harness that includes two relays.
230004HW
It plugs n plays no hacking of any original wiring.
This harness also takes away the load from the headlight switch and foot dimmer switch.

Hope this helps.

Hi CBARGE, as I look at this Putco harness, I wonder if the sockets are correct for the old-style sealed beam headlights on the Newport. Please advise. Thanks

 

[cbarge]

Hi CBARGE, as I look at this Putco harness, I wonder if the sockets are correct for the old-style sealed beam headlights on the Newport. Please advise. Thanks

Yes they are.
I have installed this kit in over a dozen mopars. They may look cheap but have not had any issues with them.
The relays are very common as in available anywhere should they need replacing.

 

[cbarge]

Here is a thread pertaining to the headlamp harness upgrade.
Dim headlights

 

[Toolmanmike]

Im with Dave and go with an electronic voltage regulator.
Autozone sells a plug n play # VR706.
To totally get rid of the headlight dimming, I recommend installing a headlight harness with relays.
I use the Putco harness that includes two relays.
230004HW
It plugs n plays no hacking of any original wiring.
This harness also takes away the load from the headlight switch and foot dimmer switch.

Hope this helps.

So does @crackedback a member here. He has built 100's of quality harness' for this issue. For Sale - Headlight relay kit..ePay...

 

[Big_John]

You can always just build your own too. Cheaper with good relays.
Headlight Relays with Hidden Headlights


BUT!!

Here we go again, doing mods without fixing the problem first. Your issue is caused by varying voltage, most likely due to the old style (assuming that is what you have) voltage regulator.

Everyone really, really means well with the relay suggestion AND while it is a very good mod, fixing the issue should take priority. After you get that squared away, go for the relay mod if you'd like.

 

[Scoopy G]

CBARGE, I got the Putco harness, but it only has two sockets for the headlamp bulbs. My Newport has 4 headlamps. Do I have the right harness? Or are the two inner lamps not used, and the two outer lamps changed to two-filament lamps?

Confused here in rainy Tampa, Rich

 

[live4theking]

Scroll up and read the link that cbarge put in his post.

 

[Scoopy G]

I did consult that link, Old Man With The Hat, and it did not provide details with regards to the two-socket harness being compatible with the 4-headlamp setup on my 67 Newport. So what do you know about this?

It seems that many guys on this forum, instead of providing answers, simply assume that posters (myself in particular) are not researching these topics before I post. One other guy with a hat is particularly condescending. And what is with this Old Man With a Hat thing anyway?

 

[65sporty]

And what is with this Old Man With a Hat thing anyway?

When you reach 5,000 posts you achieve this status, you have been around a while to get 5,000 posts. Most of us try to be helpful

 

[Scoopy G]

Sometimes I wonder if "Old Man With An Attitude" might be more accurate, present company 65sporty excepted of course.

 

[65sporty]

Sometimes I wonder if "Old Man With An Attitude" might be more accurate, present company 65sporty excepted of course.

For certain guy's, yes it fits

 

[Scoopy G]

PROBEM FIXED! Thanks to CBARGE and everyone else for their helpful suggestions. I started with the voltage regulator, but never ran the car at night before I went ahead and installed the Putco harness with relays. An evening road test confirms bright lights that don't oscillate, so all is good.
I did take the car out for a little car show this afternoon, but it was still a bit too hot here to walk around a parking lot for very long. Weather should be improving shortly, 6+ months of 75 degrees and sunny.

Cheers and thanks again to all,

Rich in Tampa