Verify voltage matches the solenoid rating (e.g., 24V DC, 120V AC) with a multimeter.

Ensure proper wiring and no blown fuses/breakers.

Measure resistance with a multimeter:

• Infinite resistance = open circuit (burnt coil)
• Zero/low resistance = short circuit

Listen for a click when energized (no sound indicates coil failure).

Look for loose, corroded, or damaged wires.

Test continuity from the control signal to the solenoid.

Low voltage at the solenoid suggests excessive line resistance or undersized wiring.

If power is correct but the valve doesn't shift:

• Stuck spool (clean or replace)
• Blocked/leaking air supply (verify pressure)

Moisture or heat can degrade coils—ensure proper IP rating (e.g., IP65).