Cooling System—Testing For Leaks - Dodge 2000 DURANGO Service Manual

7 - 16 COOLING SYSTEM
DIAGNOSIS AND TESTING (Continued)
Fig. 19 Electrical Cooling Fan
1 – RADIATOR
2 – ELECTRIC FAN ASSEMBLY
3 – FAN SHROUD (LOWER)
4 – SCREW
Test Procedure:
(1) Inspect 10A fuse in junction block and 40A
maxi fuse in PDC (Fig. 20).
(2) Remove Cooling Fan Relay from the PDC and
make the following checks at the relay connector:
• Apply 12 volts (using a fused 14-gauge wire) to
circuit C25 (relay terminal 87). If fan does not come
on, check for open in circuit C25 or Z1. If circuits are
o.k., replace the cooling fan motor.
• With the ignition key "off" check for battery volt-
age at circuit C28 (relay terminal 30). If no battery
voltage present check for open/shorted circuit C28
between the PDC and relay.
• With the ignition key in the "run" position check
for battery voltage at circuit F18 (relay terminal 86).
If no battery voltage present, check for open/short in
circuit F18 between the junction block and the relay.
• If no problems are detected, install the DRB
(refer to the appropriate Powertrain Diagnostic Pro-
cedures manual for DRB scan tool operating instruc-
tions) and start the engine. Clip a 12V test light to
the battery positive terminal and probe circuit C27
(relay terminal 85). When the engine temperature
reaches 110° C (230° F), or A/C is requested, the test
light should light. If not, check circuit C27 for open.
• If no problems are detected at this point, replace
the cooling fan relay.
Fig. 20 Power Distribution Center (PDC)
1 – POWER DISTRIBUTION CENTER (PDC)
RADIATOR COOLANT FLOW CHECK
Use the following procedure to determine if coolant
is flowing through cooling system.
(1) Idle engine until operating temperature is
reached. If upper radiator hose is warm to the touch,
thermostat is opening and coolant is flowing to radi-
ator.
WARNING: HOT, PRESSURIZED COOLANT CAN
CAUSE INJURY BY SCALDING. USING A RAG TO
COVER RADIATOR PRESSURE CAP, OPEN RADIA-
TOR CAP SLOWLY TO FIRST STOP. ALLOW ANY
BUILT-UP PRESSURE TO VENT TO THE RESERVE/
OVERFLOW TANK. AFTER PRESSURE BUILD-UP
HAS BEEN RELEASED, REMOVE CAP FROM
FILLER NECK.
(2) Drain a small amount of coolant from radiator
until ends of radiator tubes are visible through filler
neck. Idle engine at normal operating temperature. If
coolant is flowing past exposed tubes, coolant is cir-
culating.
COOLING SYSTEM—TESTING FOR LEAKS
ULTRAVIOLET LIGHT METHOD
A leak detection additive is available through the
parts department that can be added to cooling sys-
tem. The additive is highly visible under ultraviolet
light (black light). Pour one ounce of additive into
cooling system. Place heater control unit in HEAT
position. Start and operate engine until radiator
upper hose is warm to touch. Aim the commercially
available black light tool at components to be
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