Dodge ram truck 3500 1996 Service Manual page 389

B R IGNITION SYSTEM 8D - 7
D E S C R I P T I O N A N D O P E R A T I O N (Continued)
INTAKE MANIFOLD AIR TEMPERATURE SENSOR
For an operational description, diagnosis and
removal/installation procedures, refer to Group 14,
Fuel System.
IGNITION SWITCH AND KEY LOCK CYLINDER
The ignition switch is located on the steering col­
umn. The Key-In-Switch is located in the ignition
switch module. For diagnosis of the Key-In-Switch,
refer to Group, 8U.
A column shift interlock device is used to lock the
transmission shifter in the Park position when the
key is in the Off position. The interlock device is
located within the steering column assembly and is
not servicable. I f repair is necessary, the steering col­
umn assembly must be replaced. Refer to Group 19,
Steering for procedures.
D I A G N O S I S A N D T E S T I N G
AUTOMATIC SHUTDOWN (ASD) RELAY
The Automatic Shutdown (ASD) relay is located in
the Power Distribution Center (PDC). The PDC is
located in the engine compartment (Fig. 10). Refer to
label on PDC cover for relay location.
To perform a complete test of the ASD relay and its
related circuitry, refer to the appropriate Powertrain
Diagnostic Procedures service manual. To test the
relay only, refer to ASD and Fuel Pump Relays in
Group 14, Fuel System.
Fig. 10 Power Distribution Center
TESTING FOR SPARK AT COIL—3.9L/5.2L/5.9L
ENGINES
CAUTION: When disconnecting a high voltage
cable from a spark plug or from the distributor cap,
twist the rubber boot slightly (1/2 turn) to break it
loose (Fig. 11). Grasp the boot (not the cable) and
pull it off with a steady, even force.
Fig. 11 Cable Removal
(1) Disconnect the ignition coil secondary cable
from center tower of the distributor cap. Hold the
cable terminal approximately 12 mm (1/2 in.) from a
good engine ground (Fig. 12).
Fig. 12 Checking for Spark—Typical
WARNING: BE VERY CAREFUL WHEN THE
ENGINE IS CRANKING. DO NOT PUT YOUR HANDS
NEAR THE PULLEYS, BELTS OR THE FAN. DO NOT
WEAR LOOSE FITTING CLOTHING.
(2) Rotate (crank) the engine with the starter
motor and observe the cable terminal for a steady
arc. I f steady arcing does not occur, inspect the sec­
ondary coil cable. Refer to Spark Plug Cables in this
group. Also inspect the distributor cap and rotor for
cracks or burn marks. Repair as necessary. I f steady
arcing occurs, connect ignition coil cable to the dis­
tributor cap.
(3) Remove a cable from one spark plug.
(4) Using insulated pliers, hold the cable terminal
approximately 12 mm (1/2 in.) from the engine cylin-