Dodge RAM TRUCK 1500 1995 Service Manual page 1195

B R
Fig. 33 Power Distribution Center (PDC) Location
The relay terminal numbers (Fig. 35) can be found
on the bottom of the relay.
• Terminal number 30 is connected to battery volt­
age and can be switched or B+ (hot) at all times.
• The center terminal number 87A is connected (a
circuit is formed) to terminal 30 in the de-energized
(normally OFF) position.
- GENERAL DIAGNOSIS—DIESEL ENGINE 14 -113
Fig. 34 Fuel Heater and Fuel Shutdown Solenoid
Relays—Diesel
• Terminal number 87 is connected (a circuit is
formed) to terminal 30 in the energized (ON) posi­
tion. Terminal number 87 then supplies battery volt­
age to the component being operated.
• Terminal number 86 is connected to a switched (+)
power source.
• Terminal number 85 is grounded by the power-
train control module (PCM).
T E S T I N G
(1) Remove relay before testing.
(2) Using an ohmmeter, perform a resistance test
between terminals 85 and 86. Resistance value
(ohms) should be 75 ±5 ohms for resistor equipped
relays.
(3) Connect the ohmmeter between terminals num­
ber 87A and 30. Continuity should be present at this
time.
(4) Connect the ohmmeter between terminals num­
ber 87 and 30. Continuity should not be present at
this time.
(5) Use a set of jumper wires (16 gauge or small­
er). Connect one jumper wire between terminal num­
ber 85 (on the relay) to the ground side (-) of a 12
Volt power source.
(6) Attach the other jumper wire to the positive
side (+) of a 12V power source. Do not connect this
jumper wire to relay at this time.
CAUTION: Do not allow the ohmmeter to contact
terminals 85 or 86 during these tests. Damage to
ohmmeter may result.
(3) Test the resistance of the wire harness. Do this
between the powertrain control module (PCM) wire
harness connector terminal 21 and the sensor con­
nector terminal. Also check between terminal 4 to the
sensor connector terminal. Repair the wire harness
as necessary if the resistance is greater than 1 ohm.
POWERTRAIN CONTROL MODULE TESTING
Operation of the powertrain control module (PCM)
is tested with the DRB scan tool. Refer to the appro­
priate Powertrain Diagnostic Procedures service
manual for tests.
RELAYS—OPERATION/TESTING
To perform a complete test of a relay and its cir­
cuitry, refer to DRB scan tool and appropriate Pow­
ertrain Diagnostics Procedures manual. To test the
relay only, refer to the following:
OPERATION
The following operations/tests apply to these
relays only: automatic shutdown (ASD), fuel shut­
down solenoid and fuel heater. For operations/tests
on all other relays, refer to the appropriate section of
this service manual.
The ASD relay is located in the power distribution
center (PDC). The PDC is located in the engine com­
partment (Fig. 33). For the location of this relay
within the PDC, refer to PDC cover.
The fuel heater and fuel shutdown relays are lo­
cated in the engine compartment near the brake
master cylinder (Fig. 34).
FUEL SHUT-OFF
FUEL HEATER SOLENOID RELAY