I'm unfamiliar with a "signal minder". But if it is a 2-prong flasher substitute, it most likely will not work. Our ST machines are blessed with a three-prong electronic flasher, and not a simple bi-metallic heat-type unit. It took me a lot more effort to connect my "simple" Sonalert to my ST2. After trying at the flasher (where I normally connect it easily), I had to take voltages from both left and right bulbs, and pass them thru diodes, and then to the Sonalert (beeper). Bigger PITA than I had anticipated!