Dodge RAM TRUCK 1500 1995 Service Manual page 639

B R
8W-33 WEHiGLE SPEED CONTROL 8W - 33 - 1
VEHICLE SPS
VEHICLE SPEED CONTROL
The vehicle speed control system is operated by the
Powertrain Control Module (PCM). The vehicle speed
control switches are located in the steering wheel, be­
low the airbag.
Circuit V34 from fuse 10 in the fuse block supplies
battery voltage to the vehicle speed control ON/OFF
switch. Circuit A21 supplies voltage to fuse 10 when
the ignition switch is in the START or RUN position.
In the START or RUN position the ignition switch
connects circuit A21 with circuit Al. Fuse 3, a 40
amp, in the Power Distribution Center (PDC) pro­
tects circuit Al.
The vehicle speed control ON/OFF switch supplies
voltage to the SET/COAST and RESUME/ACCEL
switches. Both switches send signals to the PCM
(which supplies the ground path for the switches).
The PCM controls the vent and vacuum functions
of the vehicle speed control servo on circuits V35 and
V36. Depending on the signal it receives from the ve­
hicle speed control switches, the PCM either applies
vacuum to, or vents vacuum from, the servo. Circuit
V36 from cavity 33 of the PCM sends the vacuum
signal to the servo. Circuit V35 from cavity 53 sends
the vent signal.
Circuit V32 signals to the PCM that the speed con­
trol switch is in the ON position. The V32 circuit con­
nects to cavity 49 of the PCM. Circuit V32 also
connects to the stop lamp switch.
In the CLOSED position, the stop lamp switch con­
nects circuit V32 with circuit V30 to power the speed
control servo. Circuit Zl provides ground for the
speed control servo.
ED CONTROL
Circuit V31 provides the SET/COAST signal to cav­
ity 48 of the PCM. Circuit V33 sends the RESUME/
ACCEL signal to cavity 50 of the PCM.
Circuit V40 connects to cavity 29 of the PCM and
to ground through the stop lamp switch. The stop
lamp switch OPENS when the operator presses the
brake pedal. The PCM disables speed control when
the stop lamp switch opens. From the stop lamp
switch, circuit Z l l provides ground for circuit V40.
HELPFUL INFORMATION
• Circuit V40 also connects to the ABS control mod­
ule on vehicles with all wheel anti-lock brakes
o Circuit V40 also connects to the RWAL control
module on vehicles with rear wheel anti-lock brakes
® Check the 40 amp fuse located in cavity 3 of the
PDC
© Check the 2 amp fuse located in cavity 10 of the
fuse block
DIAGRAM INDEI
Component Page
Fuse 3
( P D C n ~ ~ ~ • " " •
777777
. ."".78W-33-2
Fuse 10 8W-33-2
Ignition Switch . . 8W-33-2
Powertrain Control Module .8W-33-2
Stop Lamp Switch .8W-33-3
Vehicle Speed Control Servo 8W-33-2
Vehicle Speed Control Switch .8W-33-2