Headlight switch

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    The headlights are too dim on my 1933 1236. Would cleaning the wires at the bottom of the steering shaft help? In other words the device that turns when the headlight switch on the steering column is moved. I believe there was a cover, of which my car does not have. Any help would be appreciated.



    Dim lights are caused by a bad ground. Often paint on the fenders causes problems. Run a jumper wire from the light housing to another good known ground and see if it gets brighter. A bad ground will cause high amperage loads, so be careful.


    Ed is right, of course, but the question is, are both headlights dim approximately the same amount? Are the high and low beams both dim? David Coco had a nice thread with sources for re-silvering the headlight reflector earlier, but the likely source here is a bad ground. One way to test it would be to remove the front lens, pull the reflector assembly with the wires still attached, and clip a jumper with a couple of alligator clips on each end to the light bulb ground on one side and a known good ground source, preferably the battery ground on the other. In this case, it is the positive terminal, as these cars were positive ground. If this improves the light intensity, the ground is the problem. If it doesn’t, try a new bulb, and/or check the voltage at the bulb terminal to a known ground, then check the voltage between the battery terminals. If there is a significant difference, more than a half volt or so, better figure the voltage supply, including the circuit through the headlight switch that feeds the headlights, should be checked further. I am a big fan of sanding terminals with some 400 sandpaper or spraying electric contact cleaner and applying dialectric grease for all terminals when maintaining a car’s electrical system.

    Any questions, feel free to catch me off line [email protected].



    A quick comment—Dialectric grease is a NONconductor. It does NOT enhance conductivity. But it helps to prevent corrosion.



    Jak, long time no hear! You are absolutely correct that it is not a conductor. It’s purpose is to prevent corrosion, especially in parts around the battery, where there are a lot of chemicals that react with metals (Lead acid) and where road spray or blowby from the engine is a factor. Any time you are joining two different metals, such as copper and bronze or steel, it creates an electrical reaction, electrolysis. Remember when you touched a spoon or fork to one of your amalgam metal fillings? Same idea.


    Good morning Bob—-How could I have forgotten the “Tooth effect”!! Once experienced, never forgotten! I am older than I thought!


    Hi Donald. I’m sure the problem is as mentioned above, poor grounds to the headlight bulbs.

    From the headlight bulb to the grounded side of the car’s battery had quite a few connections, any of which could have enough corrosion to cause a voltage drop across the connection, resulting in dim, yellow lights.

    Starting at the bulb itself, the lead buttons on the end of the bulb can have some white lead-oxide corrosion on them.

    The base of the bulb, the brass or nickeled 1/2″ diameter tube that the glass bulb and filaments are sealed into can have corrosion at the two pins, or the outside of the tube where it contacts the socket in the reflector.

    The bulb socket in the reflector is held under tension by a loop of coil spring. This allows the socket to be moved in and out of the reflector in order to focus the headlight beam. The electrical connection between the bulb, the socket, and the receptacle in the reflector should all have a light sanding with 400 grit sandpaper in order to remove any corrosion, and provide clean shiny metal to metal contact.

    Next, is the reflector to the fender.. The ’33 reflectors have two rather intricate hinges or swivel points at the 3 and 0 o’clock positions. The vertical aim of the reflector is adjusted and held by a spring-tensioned slotted head screw at the bottom of the reflector.

    Bothe hinge/pivots and the adjusting screws are attached to a potmetal clamping/mounting ring that is screwed to the lip of the headlight fairing in the fender. The hinge/pivots are fastened to the reflector with tiny carriage bolts, and to the pot metal mounting ring with small machine screws. The hinge/pivot is made of pot metal, and has a brass pivoting axle or pin.

    Any of the screws, tiny bolts or the pivot pin can have a poor connection.

    Then there is the pot metal mounting ring being screwed to the lip of the fender’s sheet metal fairing for the headlight. The fairing is painted, so only the threads and the small heads of the mounting screws make an electrical connection. This connection is also prone to corrosion of the screws to the lip of the fender fairing.

    The fender is held to the car by a row of bolts along the frame, The frame and the fender are both painted, lending it towards having poor electrical connection. There is a fender brace that is brazed or soldered to the inside of the front fender, just behind the headlight fairing. The brace follows the curve of the inside of the fender down to the frame, where it is bolted to the frame.

    Any of the fender brace bolts can have a bad connection to the frame.

    From the frame, to the Positive battery post is also a likely location for a poor ground connection.

    For my ’33 Club sedan, I ran an independent ground wire from a wire loop connector that is under one of the 4 bolts on the fender frame, the frame is sanded clean of paint and rust, to provide a good electrical connection. The wire is run inside the fender brace, along side of the normal headlight wiring. The added ground wire must follow the headlight wires into the inside of the headlight fairing.

    Then, the end of the independent ground needs to be soldered to the rear of the reflector, or the best place is to the outside of the socket that the headlight bulbs are inserted into. This independent wire eliminates several potential bad connections, and this method is highly recommended.

    Hope this helps.

    Greg Long


    I ran a home made ground harness to all my lights when we restored my 1936 1602 club sedan. With all the paint on the car it just seemed easier to do. It worked out well, and the wires are all run where you can’t see them as Greg explained in his detailed post. Ed.


    At my request, YnZ ran a ground wire to all components when making up the harness for my 1703. A great way to solve all those grounding issues, if you are rewiring the whole car.

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