Thank you for your reply/help to my questions. on the 2019 MB Sprinter 170 they're two wires to the OEM "hand-brake"; however, I still don't see how connecting a transformer to these wires will turn on/off the "hand-brake warning light" on the dash when engaging the E-Stopp button as there is no signal from the E-Stopp to the OEM "hand-brake" wires??I used a simple transistor like this:
View attachment 176686
That's just an example, not the exact one I used. This will replace the OEM parking brake contact switch. Without pulling my seat I can't remember exactly how it was wired, so you'll just have to experiment.
WRT the cable, obviously a straight cable is preferred. A slight bend shouldn't create a wear problem however.
When pulling the OEM "hand-brake lever" there is contact of the two wires and, therefore, a signal is sent to the dash that reflects on the dash as a "parking brake warning light".