– Park machine safely.
 – Disconnect wiring harness from switch.
 – Attach ohmmeter leads across the switch terminals (A).
 – Shift the transmission range to high or low.
– Range in gear position: no continuity
– Neutral position: continuity
 – If continuity is not correct, drain the transmission and remove switch.
 – Test switch continuity in OPEN and CLOSED positions.
– OPEN (plunger released): no continuity
– CLOSED (plunger depressed): continuity
If any continuity is NOT correct, replace switch.
If continuity is correct with switch removed, but not with switch installed in transmission, see the power train repair Section 50.