Storch Airless ST 850 Mode D'emploi page 173

How to check
6. Connect the Red and Black leads from the motor to an Ohm meter.
Rotate the motor while checking for opens. If an open is found replace the motor.
7. Check motor thermal protection. Motor should be at ambient temperature
for this test. Connect the yellow leads from the motor to an Ohm meter.
Meter should indicate continuity or Ohms depending on the motor type.
8. Use an Ohm meter to check motor for shorts. Connect (–) meter lead
to motor case. Move the (+) meter lead to each motor wire. Meter should
read open on all wires.
9.Reconnect motor connector(s) to control board socket(s). Connect power,
turn ON/OFF switch ON and control knob to 1/2 turn clockwise.
If motor does not run, replace control board.
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black
red
yellow
black
red
yellow
ground
black
red
yellow
Original instruction