Circuit to control an exhaust bypass valve motor via an OEM Mercedes W124 defogger switch.
W124 defogger switch is a momentary toggle switch (SPDT) with center off. Pressing the switch up, opens the bypass valve powering the motor via the timers.shop relay. The timer relay only powers the output for a programmed amount of time to avoid burning out the motor when it comes to a stop.
Pushing the switch down reverses the polarity of the output via the DPDT relay and closes the bypass valve. This also goes through the timer relay and only powers the output for the programmed time.
|1||Momentary SPDT switch||SW1||NONE||1||Yes|