View Full Version : headlight flicker and brightens on own

09-01-2006, 11:21 PM
What part of an alternator electrical system is causing lights to brighten on their own---they go from dim to a little brighter but not as bright as when using the dimmer switch. Also what causes headlight short-mild flicker on a 1960 Lark generator system ???...thanks...brad

09-01-2006, 11:57 PM
Seems like every old car I've ever owned had this problem, and the culprit was usually the voltage regulator. But more often than not, it's not the regulator itself that's the problem - it's the connections to it.

First thing I do when I get a car is to remove the regulator and clean all external contacts. I clean the spade contacts on the wires leading to it, too; DeOxit is beautiful for this.

Then, when reinstalling, make sure the ground is adequate. Often the problem is no more than a bad ground connection due to corrosion or dirt; if you make sure that the mounting points on the firewall are clean wherever a screw enters, this is 90% of the fix. You may actually want to use an external lock washer behind the regulator on each bolt to give a little extra "bite" into the firewall.

Usually, this does the trick. If this doesn't help, get a new regulator. You can service the old ones, but it's tricky and hard to do.


Clark in San Diego
'63 Lark Standard

09-02-2006, 12:46 AM
On the alternator, the ampmeter "bounce" is most often bad points in the regulator. I and other Stude. vendors sell a really good Electronic Voltage Reg. that stops the slight movement, but if it is bouncing more than half of the scale it could be a bad diode in the Alternator.
The generator system may need contacts cleaned as has been recommended, but also probably needs a good regulator. Shine a light into the rear of the generator and see if you can see the condition of both brushes they should be 3/4 to 1 in long and contacting the armature. Check the brush springs, they often rust though and break. The shop manual shows how to test the system also.

Studebakers Northwest
Ferndale, WA

09-02-2006, 07:44 AM
Where good grounds are necessary, I've become a big advocate of adding a star washer. I've sometimes found the problem to be the ground between headlight bucket and body.

Brad Johnson
Pine Grove Mills, Pa.
33 Rockne 10
51 Commander Starlight
53 Commander Starlight
previously: 63 Cruiser, 62 Regal VI, 60 VI convertible, 50 LandCruiser

09-02-2006, 10:20 AM
I agree that the problem is the regulator. I remember as a kid that you could always spot an old MoPar because they'd be the cars with the flickering headlights. A solid state regulator really is a good thing. But sort of but not really related, is a set of relays for the headlights:


I've put E-code Cibies in my 944 following this procedure and the results are so good that I think I will probably do the same to my '55 (same headlights, standard 7" round format) Anyone that drives at night would appreciate this conversion. Only downside is that the E-codes are technically not legal in the US, despite the fact that their beam pattern is such that it allows the use of much higher wattage bulbs without causing glare to oncoming drivers (at least on low beam.)


55 Commander Starlight