Dodge RAM TRUCK 1500 1995 Service Manual page 1129

COMPONENT DESCRIPTION/SYSTEM OPERATION—EXCEPT DIESEL 14 - 47
SPEED CONTROL—PCM PINS #53 AND #33—PCM
OUTPUT
These two circuits control vent and vacuum opera­
tion of the speed control solenoids.
TORQUE CONVERTOR CLUTCH (TCC) SOLENOID—
PCM PIN #54—PCM OUTPUT
AUTOMATIC TRANSMISSION
This circuit (Fig. 35) controls operation of the
transmission mounted torque convertor (TCC) sole­
noid used for torque convertor engagement.
TORQUE CONVERTER CLUTCH
AND OVERDRIVE SOLENOID
ELECTRICAL CONNECTOR
VEHICLE
SPEED
SENSOR J9414-59
Fig. 35 Electrical Connections at Transmission—
TCC and Overdrive Solenoids
The powertrain control module (PCM) will deter­
mine when to engage and disengage the solenoid by
monitoring vehicle miles per hour (mph) versus the
output voltage of the throttle position sensor. Also
needed are various inputs from:
© Engine coolant temperature
® Module timer
© Engine rpm
© MAP sensor
MANUAL TRANSMISSION
If equipped with a manual transmission, pin #54
will control operation of the shift indicator lamp (if
equipped with lamp). The lamp is controlled by the
powertrain control module (PCM). The lamp illumi­
nates on the instrument panel to indicate when the
driver should shift to the next highest gear for best
fuel economy. The PCM will turn the lamp OFF after
3 to 5 seconds if the shift of gears is not performed.
The lamp will remain off until vehicle stops acceler­
ating and is brought back to range of up-shift lamp
operation. This will also happen if vehicle is shifted
into fifth gear.
The indicator lamp is normally illuminated when
the ignition switch is turned on and it is turned off
when the engine is started up. With the engine run­
ning, the lamp is turned ON/OFF depending upon
engine speed and load.
OVERDRIVE SOLENOID—PCM PIN #55—PCM
OUTPUT
AUTOMATIC TRANSMISSION
This circuit controls operation of the transmission
mounted overdrive solenoid (Fig. 35) used for over­
drive operation. The powertrain control module
(PCM) will determine when to engage and disengage
the solenoid by monitoring engine rpm versus output
voltage of the throttle position sensor. Also needed
are various inputs from:
• Engine coolant temperature
© Transmission temperature sensor (certain heavy-
duty applications only)
© Module timer
• Vehicle speed
© MAP sensor
SRI LAMP—PCM PIN #56—PCM OUTPUT
This circuit controls operation of the SRI lamp.
The instrument panel mounted service reminder
indicator (SRI) lamp is used only on vehicles
equipped with 5.9L V-8 or 8.0L V-10 heavy duty cycle
(HDC) engines. The lamp is displayed on the instru­
ment panel as the MAINT REQ'D lamp (Fig. 36).
When the lamp has been activated, certain service/
maintenance must be performed.
For required service/maintenance stated in time or
mileage, refer to Group 0, Lubrication and Mainte­
nance. Also refer to Group 25, Emission Control Sys­
tem for additional information.
The SRI lamp is not used with the diesel engine.
SERVICE REMINDER
INDICATOR LAMP
Fig. 36 SRI (MAINT REQ'D) Lamp Location