Subaru 2002 IMPREZA Service Manual page 1769

SWITCHES AND HARNESS
MANUAL TRANSMISSION AND DIFFERENTIAL
3. HIGH-LOW SWITCH
1) Turn ignition switch to OFF.
2) Disconnect connector high-low switch.
3) Measure the resistance between high-low
switch terminals.
Gear shift position Terminal No. Specified resistance
LO position Less than 1Ω
1 and 2
HIGH position More than 1MΩ
B3M2134
4) Replace defective parts.
MT-45