Thanks Mattax !
I've been studying the heck out of the 1979 electrical schematics. When I first posted, I wasn't sure if the
plug-in flasher units were voltage sensitive, the hazard and the turn signal units.
But now I have additional uncertainty about how the parking lights and the turn/hazard light system even works.
I can't make sense of the circuits, the current flow. The schematic does not show the bulbs to be grounded,
so where is the end of the circuit ?
I don't have the full schematics - just the pages 2 through 5 that Krautrock posted in another thread.
My guess is yes they are grounded. Maybe the socket is in direct contact with metal housing?
As far as voltage sensitivity - indirectly yes they are.
The flasher units have a metal or bi-metal strip the current flow through. The current heats up the strip, and it bends or snaps away from the contact breaking the circuit until it cools again.
Current drawn by any bulb is voltage dependent.
Lets take an 1157 bulb's brighter filment as an example.
It's rated to draw 2.1 amps at 12.8 Volts.
When provided power at high voltage, say 14.5 Volts, it will draw more current. It will also burn hotter and brighter.
Yes - Give it too much voltage and it will burn itself out kindof like a fuse.
The catch is that the bulbs must see that higher voltage to draw more current.
Even when the alternator is producing power at 14.5 Volts, resistance in the connections leading to the turn signal circuit will reduce the voltage to some extent.
I'll look at the diagrams I do have and see if it the turn signal and parking light circuits look similar to the set up in my '67 Barracuda or '85 Grand? Wagoneer
