Dodge RAM 1500 1998 Owner's Manual page 2213

21 - 510 TRANSFER CASE - NV243
SELECTOR SWITCH
DESCRIPTION
The selector switch assembly (Fig. 84) is mounted
in the left side of the vehicle's Instrument Panel (IP)
and consists of a rotary knob connected to a resistive
network for the mode and range shift selections. Also
located in this assembly is a recessed, normally open
momentary switch for making shifts into and out of
transfer case NEUTRAL. A pen, or similar instru-
ment, is used to make a NEUTRAL shift selection,
thus reducing the likelihood of an inadvertent shift
request.
The selector switch also contains four light emit-
ting diode's (LED's) to indicate the transfer case posi-
tion and whether a shift is in progress.
Fig. 84 Transfer Case Selector Switch
1 - SELECTOR SWITCH
OPERATION
As the position of the selector switch varies, the
resistance between the Mode Sensor supply voltage
pin and the Mode Sensor output will vary. Hardware,
software, and calibrations within the Transfer Case
Control Module (TCCM) are provided that interpret
the selector switch resistance as given in the table
below: SELECTOR SWITCH INTERPRETATION
SELECTOR SWITCH INTERPRETATION
Step Resistance
Range (ohms)
A
B
C 1050-1450
D 1850-2300
E 3050-5950
F
G
For resistances between the ranges B-E shown for
each valid position (T-Case NEUTRAL, 4LO, 4HI,
2WD), the TCCM may interpret the resistance as:
• either of the neighboring valid positions.
• as an invalid fault position.
For resistances between the ranges E and F shown
for 2WD and in-between positions, the TCCM may
interpret the resistance as:
• the 2WD position.
• an invalid fault position.
• a valid in-between position.
For resistances between the ranges F and G shown
for in-between positions and fault condition (open),
the TCCM may interpret the resistance as:
• a valid in-between position.
• an invalid fault position.
For resistances between the ranges A and B shown
for the fault condition (short) and , T-Case NEU-
TRAL, the TCCM may interpret the resistance as:
• the T-Case NEUTRAL position.
• an invalid fault position.
The LED's in the selector assembly are illuminat-
ed/flashed in the following manner to indicate a par-
ticular condition or state.
• A solidly illuminated LED indicates a success-
fully completed shift and the current operating mode
of the transfer case. While a shift has been requested
but not yet completed, the LED for the desired trans-
fer case position is flashed.
Required
Interpretation
<200 Shorted
400-700 NEUTRAL
4LO
4HI
2WD (Default)
9.5-12.5K In between
positions
>15.5K Open
DR