Komatsu WA320-5H Operation & Maintenance Manual page 252

ATTACHMENTS, OPTIONS
MACHINE MONITOR WITH LOAD METER
LOAD METER SUB TOTAL SWITCH 6
Press switch (5) at the side of the bucket control lever to set the
TOTAL LOADED display (when in addition mode) or REMAIN-
ING TARGET display (when in remain mode) to 0.
6-5