Sorry for not responding earlier to your email. I'm a little overwhelmed right now.

Yes, if there were ports, plugs or a terminal strip for leads a larger relay could be tested on the controller.

We had a car that would run for hours without fail. But after so many hours, the car overload would trip when the brake failed to lift. Everything would ring out fine on the brake relay. I didn't want to just bang the car on and off. So, With one of your earlier version of the Wizbang tester. I made a plugin base with leads to test the brake relay on a MCE VFMC 1000. Sure enough after cycling the relay on and off many time it would fail.
Let me know what you think or just take my idea and include some modified male pugs as part of your unit...