how to use single filament lamps for turn/marker

[Calvin Krug]

I'm soon leaving the list, and would like to thank you all for your
help. Before I go, I thought I'd share something I learned while
wiring euro lights on an italian car not long ago.  If you want to
use a single element light as both a turn signal and clearance light,
here's how to do it. Cut the + wire going to the lamp Use a heavy
duty resistor (one of those big ceramic ones), I believe about 1.5 to
2 ohms, for each lamp, on the marker lamp signal wire.   On the
signal wire for the turn signals, install a diode, so that current
can only flow to the lamp, and not the other way.   Then attach the
other end of the lead from the diode and the resistor to the lamp.
Presto!  You should now have a dim light when you turn on the park
lamps, since it's only getting about 7 volts through the resistor,
but when you switch on the turn signal, it gets full 12 volts.  It's
a good idea to mount the resistor on a heat sink or large metal
surface as it will get warm.  You may be thinking "I don't need the
diode"  but you do.  without it, the 7 volts from the park lamp
circuit will flow back through the turn signal wiring, through the
other turn signal bulbs, and to ground.

If you're confused, here's a diagram:


turn signal wire______diode>___________
                                          \________(lamp)_____ground
park lamp wire_________[resistor]________/


If you're still confused, send me an email offlist, and I'll see if I can help.
Once agaain, thanks for all the assistance over the last year, and
maybe I'll be back again sometime.

Calvin K.
--
www.autosportoutfitters.com