4 X 2 Gear Selector
16
1.5.
The
electronic shift module
(ESM) processes
control inputs from the brake switch, neutral sen-
sor, and the gear selector buttons on the dash-
board. It figures out which way to move the
shifting wedge to engage the desired gear. If a
button is pushed, and the brake pedal is
depressed, the ESM energizes the solenoids
that control the vacuum to the servo that moves
the shifting wedge. The ESM is mounted on the
firewall, next to the brake pedal arm.
See Figure 1.5.
1.6.
The
solenoids
are electrically operated valves
that direct vacuum to one side of the servo or the
other. The movement of the servo (vacuum actu-
ator) is what moves the shift wedge. They are
mounted to the upper frame member at the for-
ward corner of the engine compartment, to the
left hand side. See Figure 1.6.
1.7.
The solenoids are covered by a protective rub-
ber sheet. To reach them, remove the two wing-
nuts that secure the plenum to the upper cross-
member, and carefully move the plenum aside.
The cover can be “unbuttoned” from the tow top
fasteners, and folded out of the way.
See Figure 1.7.
1.8.
The vacuum line marked with a red dot car-
ries vacuum that moves the actuator in the
“forward” direction
. This may be a movement
from neutral to forward, it may be a movement
from reverse to neutral, or it may be a movement
from reverse, past neutral to forward. The ESM
keeps track of which direction it is told to move
the actuator and whether or not the detent in the
shift wedge has passed the neutral sensor. The
vacuum line with the
red dot
should connect to
the
solenoid nearest the outside
of the vehi-
cle. That solenoid
(forward)
has
one red wire
and
one yellow wire with a black trace.
1.9.
The vacuum line marked with the green dot
carries vacuum that moves the actuator in
the “reverse” direction.
This may be a move-
ment form Neutral to Reverse, it may be a move-
ment form Forward to Neutral, or it may be a
movement from Forward, past Neutral, to
Reverse. The vacuum line with the
green dot
should connect to the middle solenoid. The
middle (reverse)
solenoid has
one red wire
and
one orange wire.
Figure 1.5
Electronic
Shift
Module
Brake
pedal
arm
Figure 1.6
Bed latch
Plenum
(removed)
SOLENOIDS
Protective
cover
Push-in fasteners
Figure 1.7
Protective cover
in place over vacuum solenoids
Summary of Contents for BIG COUNTRY 4X2
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