Dodge Durango

 Service Manual

Heating and Air Conditioning » Diagnosis and testing
Blower motor

WARNING: ON VEHICLES EQUIPPED WITH AIRBAGS, REFER TO PASSIVE RESTRAINT SYSTEMS BEFORE ATTEMPTING ANY STEERING WHEEL, STEERING COLUMN, OR INSTRUMENT PANEL COMPONENT DIAGNOSIS OR SERVICE. FAILURE TO TAKE THE PROPER PRECAUTIONS COULD RESULT IN ACCIDENTAL AIRBAG DEPLOYMENT AND POSSIBLE PERSONAL INJURY.

For circuit descriptions and diagrams, refer to Air Conditioning/Heater in Group 8W - Wiring Diagrams.

Possible causes of an inoperative front or rear blower motor include:

• Faulty fuse (the rear blower motor fuse is located in the relay and fuse block located on the back of the junction block)
• Faulty blower motor circuit wiring or wire harness connectors
• Faulty blower motor resistor
• Faulty blower motor relay (Voltage Reduction Relay or VRR) (front only)
• Faulty blower motor switch
• Faulty heater-A/C mode control switch (front only)
• Faulty high speed blower motor relay (front only)
• Faulty blower motor.

Possible causes of the front or rear blower motor not operating in all speeds include:

• Faulty fuse (the rear blower motor fuse is located in the relay and fuse block located on the back of the junction block)
• Faulty blower motor switch
• Faulty blower motor resistor
• Faulty blower motor relay (front only)
• Faulty blower motor circuit wiring or wire harness connectors
• Faulty high speed blower motor relay (front only).

VIBRATION

Possible causes of front or rear blower motor vibration include:

• Improper blower motor mounting
• Improper blower wheel mounting
• Blower wheel out of balance or deformed
• Blower motor faulty.

NOISE

To determine that the rear blower is the source of the noise, simply switch the blower motor from off to on. There are no other moving parts involved in the rear overhead A/C unit, which makes it simple to identify the source of the noise. To verify that the front blower is the source of the noise, unplug the front blower motor wire harness connector and operate the heater-A/C system. If the noise goes away, possible causes include:

• Foreign material in the heater-A/C housing
• Improper blower motor mounting
• Improper blower wheel mounting
• Blower motor faulty.

A/c performance

Blower motor

Blower motor relay

Blower motor resistor

Blower motor switch

Compressor

Compressor clutch coil

Electronic cycling clutch switch (front unit only)

Heater-a/c control

Heater performance

Dual function high pressure switch/high pressure cut-off switch

Low pressure cut-off switch

Refrigerant system leaks

Refrigerant system service equipment

Vacuum system