I spent a great deal of time in late 2017-early 2018 testing several improvement iterations of the Drake D2AZ-13341-C switch. First, I measured the static resistance through the switch. Then I measured the temperature at various rivet locations to understand how the switches fail. Simultaneously, I measured the voltage drop across the switch under load and calculated the resistance. I also measured the same points on an NOS Ford switch built in the early 1990's.The NOS switch resistance was well below .1 ohms. The Drake switch measured from .3 to .9 ohms.
I discovered that the voltage drop caused by the excess resistance was overheating the steel rivets at the green, blue, orange/blue, and green/orange wires. The rivet temperatures exceeded the melting point of the plastic housing on the original Drake switch. This is why the old Drake switches failed. They were marginal in a Mustang and not viable in a Cougar.
The manufacturer revised the switch with thicker wires, brass rivets, higher temperature plastic, and improved the material for the brake "W" contact bar.
The goal was to reduce the resistance through the switch and reduce the heating generated.
The old version would release the "magic" smoke in about 45 seconds. The final version of the revised switch was tested successfully for over 10 minutes with full brake lamp current.
Note: It is a good idea to operate the switch 10 times in each direction to clear the grease from the internal contacts.
My recommendation is to measure any new switch from the green to the orange/blue and green/orange wire - it should be near or below to .1 ohms.
Also measure from the blue to the orange/blue in the Right turn position and then blue to the green/orange wire in the Left turn position.
However, the best solution is to convert to LED bulbs and reduce the current through the switch (by a factor of 7!).
Air filter elbow duct.
Rear chrome ashtray top, or whole assembly.
Non XR7 glove box door.
Black dash pad.
And an era correct, aftermarket, tach to clamp on the steering column. An old Sun?
Let me know if you have any of these.