Dodge dakota 2002 Service Manual page 2781

24 - 6 HEATING & AIR CONDITIONING
HEATING & AIR CONDITIONING (Continued)
If the floor outlet air temperature is too low, refer
to Cooling to check the engine coolant temperature
specifications. Both of the heater hoses should be hot
to the touch. The coolant return heater hose should
be slightly cooler than the coolant supply heater
hose. If the return hose is much cooler than the sup-
ply hose, locate and repair the engine coolant flow
obstruction in the cooling system. Refer to Cooling
for the procedures.
An alternate method of checking heater perfor-
mance is to use a DRBIII scan tool to monitor the
engine coolant temperature. The floor outlet air tem-
perature reading should be no more than 4.5° C (40°
F) lower than the engine coolant temperature read-
ing.
OBSTRUCTED COOLANT FLOW Possible loca-
tions or causes of obstructed coolant flow:
• Faulty water pump.
• Faulty thermostat.
• Pinched or kinked heater hoses.
• Improper heater hose routing.
• Plugged heater hoses or supply and return ports
at the cooling system connections.
• A plugged heater core.
CONDITION
INSUFFICIENT HEATER
OUTPUT.
Heater Diagnosis
POSSIBLE CAUSE
1. Incorrect engine
coolant level.
2. Air trapped in engine
cooling system.
3. Incorrect engine
coolant temperature.
4. Blend door actuator
inoperative or defective.
5. Blend door not
operating properly.
6. Insufficient air flow
through heater housing.
7. Improper blower motor
operation.
If proper coolant flow through the cooling system is
verified, and heater outlet air temperature is still
low, a mechanical problem may exist.
MECHANICAL PROBLEMS Possible locations or
causes of insufficient heat:
• An obstructed cowl air intake.
• Obstructed heater system outlets.
• A faulty, obstructed or improperly installed
blend door.
• A faulty blower system.
• A faulty a/c heater control.
TEMPERATURE CONTROL
If the heater outlet air temperature cannot be
adjusted with the temperature control knob on the
a/c heater control panel, the following could require
service:
• A faulty a/c heater control.
• A faulty blend door actuator.
• A faulty, obstructed or improperly installed
blend door.
• An obstructed cowl air intake.
• The engine cooling system.
CORRECTION
1. Check the engine coolant level. Refer to Cooling for
the procedures.
2. Check the operation of the coolant reserve/recovery
system. Refer to Cooling for the procedures.
3. Check the performance and operation of the engine
cooling system including: thermostat, water pump, fan
drive, accessory drive belt, coolant flow (plugged radiator
or heater core, plugged or kinked coolant hoses), air flow
(missing or improperly installed radiator air seals or fan
shroud). Refer to Cooling for the procedures.
4. (Refer to Controls/Blend Door Actuator) in this group.
5. Check for a damaged, obstructed or improperly
installed blend door or seals. (Refer to Controls/Blend
Door Actuator) in this group.
6. Remove foreign material or obstructions from cowl air
intake.
7. (Refer to Distribution/Blower Motor/ Diagnosis and
Testing) in this group.
DR