Does the indicator illuminate correctly?
Yes
GO to
C7
.
No
GO to
Pinpoint Test D
.
C7
CHECK THE LOW LAMP INDICATOR — TRIGGER THE GEM ACTIVE COMMAND LOW LAMP ON
Trigger the GEM active command LOW LAMP to ON, then OFF. The LOW indicator should
illuminate, then turn off.
Does the indicator illuminate correctly?
Yes
GO to
C8
.
No
GO to
Pinpoint Test D
.
C8
CHECK THE FRONT AXLE ENGAGEMENT
Trigger the GEM active commands AXLE ENGG to ON and AXLE DSCN to OFF.
Raise and support the vehicle with the engine running; refer to
Section 100-02
.
Spin one front tire. The other front tire should spin in the opposite direction.
Is the axle disconnect working properly?
Yes
EXIT the active command modes. LOWER the vehicle. GO to
C9
.
No
GO to
C12
.
C9
CHECK THE FRONT DRIVESHAFT ENGAGEMENT
Place the mode switch in the 4H position and drive a short distance.
Raise and support the vehicle with the engine running; refer to
Section 100-02
.
The front and rear driveshafts should both spin.
Is the transfer case locking the front driveshaft to the rear driveshaft?
Yes
GO to
C10
.
No
GO to
Pinpoint Test A
.
Page 53 of 74
1998 F-150/250 Workshop Manual
1/11/2011
http://www.fordtechservice.dealerconnection.com/pubs/con...