Carrier 38MARBQ12AA1 Service Manual page 35

DIAGNOSIS AND SOLUTION (CONT)
Remarks:
• Use a multimeter to test the DC voltage between the 2 port (or S or L2 port) and 3 port (or N or S port) of outdoor unit.
• The red pin of multimeter connects with 2 port (or S or L2 port) while the black pin is for 3 port (or N or S port) the unit is normal running,
the voltage is moving alternately as positive values and negative values
• If the outdoor unit has malfunction, the voltage has always been the positive value.
• While if the indoor unit has malfunction, the voltage has always been a certain value.
• Use a multimeter to test the reactor's resistance which does not connect with capacitor.
• The normal value should be around zero ohm. Otherwise, the reactor must have malfunction.
SG-38MARB-01 Specifications subject to change without notice.
S and N
or
L2 and S
or
2 and 3
35