[urq] Marker Light Challenges

Eric Renneisen racingiron at comcast.net
Thu Jun 16 22:26:10 EDT 2005

Steve Buchholz wrote:
> ...the marker light gets a low resistance to ground 
> through the paralleled filaments for the turn 
> signals, and when the headlights are off the marker 
> light gets a low resistance to ground through the 
> headlight and taillight filaments

I always thought it was grounding back through the parking light switch
or flasher (whichever function isn't active).  The filaments will never
be low resistance, and if the current flowed through them they'd glow
dimly (as would the marker) since you've got multiple filaments in
series.  With the lights on and the flasher operating, the flasher
actually interrupts the circuit because you have +12V on both sides of
the marker filament.  Consequently, the marker flashes alternately from
the normal turn sigs when the lights are on.  Of course, I could be
completely off target with all of the above.

I definitely like the flasher function.  I'm a bit concerned about where
the current will go if the switch/flasher grounds become marginal, but
it's an easy mod to reverse on the fly.  There's a little superstition
involved too, because the incident with my '85 happened the day after I
did this.

Eric Renneisen
'93 S4
'86 urq
Chattanooga, TN

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