ok what to try next for my dim lights ?

[cherokeechief79]

all of my lights are dim and flicker slightly untill i rev it a bit higher.
i replaced the alt with a high amp one i put a new voltage regulator on and sanded the body where it sits for better ground,ran a heavy hot wire from the alt hot to the hot on the starter relay to help reduce the load to the amp gage,i checked all the grounds from body to eng and frame and added one to the body,i pulled all 3 bulkhead plugs and cleaned them and put dielectric grease on them..........i still have the same problem no change.i can even see it in the dome lamp. what is next in line to check?

 

[Bird 426]

Headlight switch?

 

[66Newport]

What's the ammeter doing when you are seeing this at low idle? What if you put a voltmeter on the battery or one of the lights.. what do you see?

 

[1967coronet]

I still run the old oem style lamps.
Napa I think. 60amp alt. But added a electronic voltage reg.
I had the same dim at idle issue.
Back when my stepdad was still alive he advised adding a 10ga. Ground wire from the neg battery terminal to the radiator support.
Cured mine .

 

[Don Frelier]

I still run the old oem style lamps.
Napa I think. 60amp alt. But added a electronic voltage reg.
I had the same dim at idle issue.
Back when my stepdad was still alive he advised adding a 10ga. Ground wire from the neg battery terminal to the radiator support.
Cured mine .

You should have a secondary ground from the back of the head to the firewall already.
Another improvement might be a new light harness from the bulkhead forward.
If you cut and strip these old wires you see they often show a black discoloration on the outside of all the strands.

 

[threewood]

What's battery voltage at idle vs. 2000 rpms?
How I solved it? Installed a Denso 60a alternator with built in regulator. At idle, with lights on, keeps 14.1v to the battery and maintains it throughout rpms.

 

[1967coronet]

You should have a secondary ground from the back of the head to the firewall already.
Another improvement might be a new light harness from the bulkhead forward.
If you cut and strip these old wires you see they often show a black discoloration on the outside of all the strands.

Thanks Don, Yes I do have a good clean braided ground from the head to firewall.
I have seen the black discolor on wiring.
For my old 67 adding that extra ground helped my head lights at idle.
I'm sure it was a band aid. I had also replaced my negative cable from battery to engine.
Thanks for the idea on a harness, that may be all it needs.

 

[vance.dykes]

check the ground from the head light to it's ground and clean it.

the head light harness is cheep insurance and less resistance.

a new style alt with built in reg, is best if your not worried about o/g

 

[AR67GTX]

You can always replace your voltage regulator with a solid state one ( assuming you have a mech one). Everyone I’ve tried puts out 15.3 to 15.5 volts at idle. Flickering and dim headlights will probably no longer be a problem. Although you may be like me and pucker up a little over those voltage levels.

Even a mech voltage regulator can be tweaked for a little more voltage if your running voltage level is low.

 

[gtx6970]

Putting the headlights on relays is a MAJOR upgrade and takes care of a lot of issues on these old cars .

 

[1 Wild R/T]

Yup.. Relays...

As Bill mentioned, it cures more than headlight issues... And here's why, on these old cars one of the biggest electrical draws is the headlights, when they are on other stuff being fed by the same wiring suffers from reduced power being available... Putting the headlights on relays mean power goes straight from the alternator to the lights without pulling power from everything else...

Even if the headlights draw the full capacity of the alternator (They shouldn't) the other stuff will still have the battery to draw off of and the full capacity of the wiring which normally was diverted to the headlights..

 

[furious70]

Second the headlight relay kit

 

[toolmanmike]

all of my lights are dim and flicker slightly untill i rev it a bit higher.
i replaced the alt with a high amp one i put a new voltage regulator on and sanded the body where it sits for better ground,ran a heavy hot wire from the alt hot to the hot on the starter relay to help reduce the load to the amp gage,i checked all the grounds from body to eng and frame and added one to the body,i pulled all 3 bulkhead plugs and cleaned them and put dielectric grease on them..........i still have the same problem no change.i can even see it in the dome lamp. what is next in line to check?

You didn't mention what year car you had. The early roundback alternators have a hard time keeping up with load at low rpm's. A headlight relay kit from Crackedback, a member here can take care of your issue. Look him up.

 

[cherokeechief79]

67 coronet wagon 318 just replaced the alt with the modern 62 amp powermaster one that requires grounding one of the leads which i did.i grounded it to the intake though.

 

[toolmanmike]

67 coronet wagon 318 just replaced the alt with the modern 62 amp powermaster one that requires grounding one of the leads which i did.i grounded it to the intake though.

The 62 amp rating is maximum output at rpm and not at idle. That's why the Crackedback kits work so well. The headlights run directly off battery power through a relay. It is much easier on the headlight switch because it only needs current to close the relay. All the current for your headlights doesn't have to travel through the bulkhead connectors and through your amp meter.

 

[cherokeechief79]

i have similar kits on my 76 jeep cherokee and my 80s monte carlos.
i plan on putting one on this too.
they work great but neither have this problem where all of the lights dim and flicker at idle.
maybe with the headlights running direct off the battery the others will come to life.

 

[oldkimmer]

What do u have for a battery? How old? What are its ratings? Which alternator is it? I’ve also had where the wires were loose on the alt gauge in the dash. Kim

 

[Photon440]

The 62 amp rating is maximum output at rpm and not at idle. That's why the Crackedback kits work so well. The headlights run directly off battery power through a relay. It is much easier on the headlight switch because it only needs current to close the relay. All the current for your headlights doesn't have to travel through the bulkhead connectors and through your amp meter.

Is that how they're measured now? The old specs (like out of the 1969 field service manual) list the output at lower rpms. For example:

 

[toolmanmike]

Is that how they're measured now? The old specs (like out of the 1969 field service manual) list the output at lower rpms. For example:


View attachment 1587906

1250 is a lot higher rpm than 650 in drive where is when the problems occur..I don't have a ac solenoid on my Swinger and I can stop the turn signals from blinking at idle with the ac on. I have to slip it in neutral to bring the rpm up. Newer alternators have higher output at idle rpm.

 

[Bob Lynch]

Contact @Crackedback (Rob) for a relay kit as others have mentioned.
I have one too('67 GTX) and my headlights are bright as heck.
No Brainer and one of the best upgrades for our cars with easy install.