WM2250CW - LG Washing Machine Service Manual (repair manual). Page 40

1. Unplug power cord.
2. Remove rear panel.
3. Remove washer top.
4. Remove main PCB assembly cover as shown in figure below.
5. Locate the white hall sensor 4-wire connector using wiring diagram wire colors

as your guide.

6. Plug in power cord, close door, and press the button. DO NOT PRESS START!
7. Place meter leads on White & Gray wires. You should read 10 to 15 V

DC

output

from the Main PCB Assembly to the Hall sensor. If no 10 to 15 V

DC

is

measured, the control board is defective.

8. Place meters leads on Blue to Gray. Turn motor rotor slowly by hand. You

should measure a pulsing 10 V

DC

. Place meter leads on Red to Gray. Turn

motor rotor slowly by hand. You should measure a pulsing 10 V

DC

. If both tests

measure a pulsing 10 V

DC

, hall sensor and harness OK. If either or both tests

measures 9 to 10 volts, but does not pulse or change, Hall sensor has failed
and must be replaced. IF zero (0) voltage is measured on either test, check red
blue wires for continuity. Repair or replace harness as needed.

7. To measure output signal voltage from the hall sensor, carefully move test

leads to terminals 1 to 4, blue and gray. Slowly rotate motor rotor by hand. 
You should read a pulsing 10 V

DC

. If 10 V

DC

is measured from 1 to 4, move

lead on blue wire to red wire, terminal 2. Repeat rotating motor rotor by hand.
You should read a pulsing 10 V

DC

from red to gray.

8. If pulsing 10 V

DC

is measured from 1 to 4 and 2 to 4, hall sensor is OK! If either

test netted only 9 to 10 V

DC

without changing (no pulsing) the hall sensor is

likely defective. Disconnect power by unplugging washer and ohm check hall
sensor to verify failure of the hall sensor.

Test Points

(1) to (2)

(1) to (3)

(1) to (4)

(2) to (4)

(3) to (4)

Result

8-12 kŸ

8-12 kŸ

10-15 V

DC

10 V

DC

10 V

DC

Remarks

Voltage Input

Pulsing Signal

Pulsing Signal