1973 Blinkers relay, What physically makes it blink? Options

[tmc914]

Still having trouble with my blinkers relay. At first both dash indicators would start blinking at the same time rapidly. Put in a new EP26 relay and all was better. Then a few months ago replaced the Brake lamp indicator (that did not work since I bought the car) and when the ebrake is on not only does the red indicator light come on but the turn signal dash indicator lamps come on and blink rapidly also. It drives me crazy because I know it isn't right.

So I bought a new modified EP26 relay from SpokesWorksLED.com (he grounds the C/C2 terminal) and it did what was expected. The left and right indicators blink reversed (that is okay for now) and when the Ebrake was on the indicator blinked nice and red. The problem is the relay keeps clicking on and off in a steady pattern. When the Ebrake is off the red light does not blink but the relay continues to cycle on and off. It is as if the blinker is on all the time (when ignition is on).

The question is: Where does that blinking signal come from to make the relay cycle on and off? By knowing where to look on some diagram I can narrow down what is happening and then fix it. I am not using LED lamps, just regular incandescent.

I can see why the previous owner left that Ebrake lamp out.