Chrysler 1998 Voyager Service Manual page 1415

NS/GS
DESCRIPTION AND OPERATION (Continued)
Fig. 6 Speed Sensor Operation
AIR CONDITIONING (A/C) CONTROLS—PCM
INPUTS
The A/C control system information applies to fac-
tory installed air conditioning units.
A/C REQUEST SIGNAL: When either the A/C or
Defrost mode has been selected and the A/C low and
high–pressure switches are closed, an input signal is
sent to the powertrain control module (PCM). The
PCM uses this input to cycle the A/C compressor
through the A/C relay.
If the A/C low or high–pressure switch opens, the
PCM will not receive an A/C request signal. The
PCM will then remove the ground from the A/C relay.
This will deactivate the A/C compressor clutch. Also,
if the engine coolant reaches a temperature outside
normal of its normal range, or it overheats, the PCM
will deactivate the A/C clutch.
BRAKE SWITCH—PCM INPUT
When the brake light switch is activated, the PCM
receives an input indicating that the brakes are
being applied. After receiving this input, the PCM is
used to control the speed control system. There is a
Primary and a Secondary brake switch. The Second-
ary brake switch is closed until the brake pedal is
pressed.
DATA LINK CONNECTOR—PCM INPUT AND
OUTPUT
The 16–way data link connector (diagnostic scan
tool connector) links the Diagnostic Readout Box
FUEL SYSTEM—2.5L DIESEL ENGINE/2.0L GAS ENGINE
(DRB) scan tool with the PCM. The data link connec-
tor is located under the instrument panel near the
bottom of steering column (Fig. 7).
VEHICLE SPEED SENSOR—PCM INPUT
The vehicle speed sensor (Fig. 8) is located in the
extension housing of the transmission. The sensor
input is used by the PCM to determine vehicle speed
and distance traveled.
Fig. 7 Data Link Connector Location
Fig. 8 Vehicle Speed Sensor—Typical
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