This is your switch. When 24V is applied here, the relay "clicks" and completes the circuit.
Check the trigger wire voltage at Pin 86 using a multimeter. If 24V is present, verify that Pin 85 has a clean, unpainted path to a solid ground. f4901 11a 24v schematic install
Connect one end of the fused red wire to the positive terminal of the power supply, and the other end to . This is your switch
Receives the +24V signaling voltage from your physical toggle switch, PLC, or ignition wire to activate the relay internal coil. the relay's electromagnetic coil energizes
EEP‑F4901‑2026‑INST Revision: 1.0 Classification: Technical Application Note
These are the input terminals for the 24V control signal. When 24V is applied across these pins, the relay's electromagnetic coil energizes, moving the internal contacts.