The coil on an A-body turn signal flasher unit is in series with the load

[Bill Crowell]

Therefore the flasher unit will only operate when a load (the selected bulb) is placed on its output. If your turn signals don't work, try connecting a test light from fuse (3) to ground. The load provided by the test light bulb will make the flasher unit operate.

The voltage source for the circuit is the ignition switch in the "run" position (1). Power goes through the curved connector under the steering column to cavity 22 on the bulkhead connector (2), where it powers both the ballast resistor and the bottom of the aforementioned turn signal flasher fuse (note difficult-to-see dotted line, 3). The other end of this fuse feeds the coil terminal of the flasher unit (4). The load terminal of the flasher unit (5) goes through the straight steering column connector to the wiper of the turn signal switch (6). All the turn signal switch does is connect the load (the selected bulb) to the power feed. Once it connects the load, the flasher unit begins to operate.

If you want to test your turn signal switch, try bypassing it by jumpering wire F3 at the straight connector to any of the turn signal light lines at that same connector, thereby connecting the load to the circuit.

 

[67Dart273]

Yeh........LOL and it's why they don't work well with LED's. "Back in the day" (expensive) Trucklite used to sell plastic cased ones you could see into. They were solid state with a relay and "claimed" they would "flash anything." But since they were for trucks, I imagine the claim leaned towards MORE load, and not less

Same idea, Signal Stat, "used to be" another great brand

I may be mistaken, I may have been thinking of Grote