Step down flasher timing

paulrhd29nzpaulrhd29nz Posts: 209Member
I’ve noticed an issue with my 51. 
When the running lights or headlights are on, the flasher rate for the turn signals is much slower on the divers side than the right side. By half I’d say. When lights are off both sides flash the same. Brightness is not affected. The passed owner had some rewiring done that looks OK. 
What should I be looking for ? As far as I can tell on the wiring diagram lights and turn signals do not cross. Any suggestions? 


  • Jon BJon B Posts: 7,085Administrator
    Are you running old-style tungsten-filament bulbs, quartz-halogens, or L.E.D.s?

    Also, is the same headlight bulb on the right and left sides?  (If you were using a more powerful bulb on one side, that could result in faster flashing.)

    Of course, if there were a short circuit anywhere along the line on one side, that would probably draw more power and cause the blinker to run faster when you turn the switch in that direction.
  • KdancyKdancy Posts: 2,439Senior Contributor
    I'm wiring up a 51 right now. 
    Check to see that your bulbs match in both fronts and rears. 
    double check grounds. If all that is good, check each wire with an ohm meter. 
    I am having an issue with the dash jewel from the flasher not working but everything else does, haven't figured it out yet. Works good on test stand, just not in car. 
  • ratlee2ratlee2 Posts: 275Expert Adviser


    One thing I found when I replaced my faulty 3 prong flasher on my Super Wasp was that the prong location (X, P, and L) locations varied depending on the part you bought.  I had to switch the locations within the wiring harness terminal to correct it.  I converted mine to 12volts, so buying a direct replacement wasn't an option.


  • squirrelsquirrel Posts: 169Member
    The only place the lights and turn signal wiring crosses, is at the bulbs, and the only way they actually will cross, is if there is excessive resistance in the ground circuit for the bulbs. If the ground is good, there is not cross over. If the ground is bad, then the light circuit acts as a ground for the bulb's turn signal circuit.

    The flasher speed depends on load. If the turn signal filament is getting grounded through the running light filament, the connection at the other end of the running light filament will act as the ground, and turning the running lights on or off will affect that ground.

    But the interesting thing is that you have the problem both with the headlights, and with the running lights....which seems strange to me.


    1. Do the front park lights turn off when you turn on the headlights?

    2. Are the rear turn signal lights on single filament bulbs? or is there also a tail light filament on them? (I think factory wiring was single, but it's possible to add a tail light to them with a different socket)

  • paulrhd29nzpaulrhd29nz Posts: 209Member
    Squirrel, yes the front running lights turn off with the headlights. The rear turn signal is a double filament with the break light. Tail light is a single. I’m going threw the grounds. 
    I’m  now wondering if the rear turn signals should be shared with the tail light and the break should be the single filament bulb ?
  • Jon BJon B Posts: 7,085Administrator
    I assume you have the 6-wire turn signal switch (in which the turn signal and brake share the bright filament of the single taillight bulb, and the "dim" filament is the taillight).  Or is it the 3-wire switch, in which there is a dedicated bulb in each taillight housing for just the turn signal?  (Or, is your turn signal switch a non-Hudson, aftermarket switch?)  I am not acquainted with the StepDowns; my 1937 has but one bulb in each taillight housing, so it's a double filament with the brake and turn signal sharing the bright filament.

    Also: you say that the front running lights turn off with the headlights.  Are you speaking of the parking lights?  They should turn on separately from the headlights.  And where are the front turn signal lights located -- are they an add-on light fixture, or are they part of the parking lights?
  • squirrelsquirrel Posts: 169Member
    edited June 2019
    The original setup (according to the wiring diagram) uses a 3 wire switch. The rear brake and tail light share the upper bulb, the turn signal is a single filament bulb below.

    But we can't see how your car was wired, we need more information.

    Also, if the tail light housing is not well grounded, it doesn't really matter if they share the bulb--the housing ground is indeed shared by all three lighting circuits. You could test the housing ground by adding an additional ground wire from the turn signal light socket, to the body.
  • Jon BJon B Posts: 7,085Administrator
    ...and as a very quick test of the "bad ground" theory, one could simply run a long wire from the positive (ground) terminal on the battery, and touch the wire to the socket of the bulb in question, while engaging the turn signal switch.  No need to go from socket to socket, installing additional ground wires from socket to body, and hoping that cures the problem.  If grounding a socket to the + battery terminal eliminates the blinking problem, you have immediately found the source of your problem.
  • RichardDRichardD Posts: 681Member
    Know your problem needs fixing, but when it is, you might want to connect the front parking lights to come on with the ignition, aka, all late model vehicles running lights. I did my '53 and feel safer. Must be done correctly; I have 2 diodes in that circuit; not sure why right now, but I must have needed when I did it.
  • squirrelsquirrel Posts: 169Member
    edited June 2019
    the diodes probably allow you to shut off the engine when the parking lights are on?

    I'd probably feel safer having the headlights on day and night, if I were concerned about it. The park lights are not very bright during the day.

  • RichardDRichardD Posts: 681Member
    edited June 2019
    Forgot, have 12 volts & LED's. Also, here are the rear signals, etc. Yes, I like being safe  & headlights are good, mine are 100W. Happen to think of all this while reading posts~~
  • squirrelsquirrel Posts: 169Member reason I like to drive old cars every now and then, is to escape the "nanny" experience of modern cars!  :)

  • paulrhd29nzpaulrhd29nz Posts: 209Member
    Safe safe is good. That’s why I’m trying to get my flasher rate up to speed. My rears are obviously wired incorrectly. I’ll re wire the turn signals to be there own bulb. And check grounds will I’m at it. 
    Thank you all !!
  • ratwaspratwasp Posts: 60Member
    anybody have the wiring diagram for lighting? (for '54) - I cannot find in Library
  • LanceLance Posts: 867Member
    Your owner manual has a wiring diagram in it.
  • 29sptphaeton29sptphaeton Posts: 280Member
    If you take your owners manual to an office supply store like Staples then can blow up the wiring diagram and print it out for you. I had this done for my 51 and it made it much easier when installing my new harness.
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