Does the PID indicate 4WD HIGH?
Yes
GO to A7.
No
GO to A8.
A7 CHECK THE 4X4 MODE SWITCH — MONITOR THE GEM PID 4WD_SW
Monitor the GEM PID 4WD_SW.
Place the mode switch in the 4X4 LOW position.
Does the PID indicate 4WD LOW?
Yes
GO to A16.
No
GO to A8.
If the PID indicates OFFO-G, GO to A14 .
A8 CHECK THE 4X4 MODE SWITCH IN THE 2WD POSITION
4X4 Mode Switch C225
Place the mode switch in the 2WD position.
Measure the resistance between the mode switch terminals 2 and 3.
2000 Ranger Workshop Manual
http://www.fordtechservice.dealerconnection.com/pubs/content/~WSYL/~MUS~LEN/21/