Heating & Air Conditioning - Service Information: NVH Dodge Dart PF

NOISE

To determine if the blower motor is the source of the noise, simply switch the blower motor from Off to On. To verify that the blower motor is the source of the noise, unplug the blower motor wire harness connector and operate the heater-A/C system. If the noise goes away, possible causes include

1. Foreign material on fresh air inlet screen
2. Foreign material in blower wheel
3. Foreign material in HVAC housing
4. Improper blower motor mounting
5. Deformed or damaged blower wheel
6. Worn blower motor bearings or brushes

VIBRATION

Possible causes of a blower motor vibration include

1. Improper blower motor mounting
2. Foreign material in blower wheel
3. Deformed or damaged blower wheel
4. Worn blower motor bearings

Scheme 50

1. Disconnect and isolate the negative battery cable.
2. Remove the passenger side silencer panel. Refer to «PANEL, SILENCER, LOWER, REMOVAL»(ref-646233-S08338251242014072800000) .
3. Remove the passenger side center console close out (2). Refer to «CONSOLE, FLOOR, REMOVAL»(ref-646233-S27686239062014072800000) .
4. Disconnect the wire harness connector (5).
5. Remove the three screws (1) that secure the blower motor (3).
6. Remove the blower motor cover (4) from the blower motor.
7. Remove the blower motor from the passenger side of the HVAC housing (2).

A/C SYSTEM NOISE

When investigating an A/C system related noise, you must first know the conditions under which the noise occurs. These conditions include: weather, vehicle speed, transmission in gear or neutral, engine speed, engine temperature, and any other special conditions. Noises that develop during A/C operation can often be misleading. For example: What sounds like a failed front engine bearing or connecting rod, may be caused by loose bolts, nuts, mounting brackets or a loose compressor clutch assembly.

Drive belts are speed sensitive. At different engine speeds and depending upon drive belt tension, drive belts can develop noises that are mistaken for an A/C compressor noise. Improper drive belt tension can cause a misleading noise when the compressor clutch is engaged, which may not occur when the compressor clutch is disengaged. Check the accessory drive belt condition and tension as described in Cooling before beginning this procedure.

1. Select a quiet area for testing. Duplicate the complaint conditions as much as possible. Turn the A/C compressor On and Off several times to clearly identify the compressor noise.
2. Loosen all of the compressor mounting hardware and retighten. Check the A/C clutch. Be certain that the clutch coil, clutch plate and pulley are mounted securely to the A/C compressor, and that the clutch plate and pulley are properly aligned and have the correct air gap.
3. To duplicate high-ambient temperature conditions (high head pressure), restrict the air flow through the A/C condenser. Install a manifold gauge set or a scan tool to be certain that the high side pressure does not exceed 3.53 Mpa (512 psi).
4. Check the refrigerant system plumbing for incorrect routing, rubbing or interference, which can cause unusual noises. Also check the refrigerant lines and hoses for kinks or sharp bends that will restrict refrigerant flow, which can cause noises.
5. Listen to the A/C compressor while the clutch is engaged and disengaged. Probe the A/C compressor with an engine stethoscope or a long screwdriver with the handle held to your ear to better localize the source of the noise. If the noise is from the A/C compressor, conduct the A/C Performance test and verify refrigerant charge level. Refer to «DIAGNOSIS AND TESTING»(ref-646220-S27172954272014072800000) .
6. If the A/C clutch and refrigerant charge level is ok, but the noise persists, replace the A/C compressor. Refer to «COMPRESSOR, A/C, REMOVAL»(ref-646220-S17088941942014072800000) .

Scheme 51

Examine the friction surfaces of the pulley and clutch plate (2) for wear. The pulley and clutch plate should be replaced if excessive wear or scoring is found.

If the friction surfaces are oily, inspect the shaft and nose area of the A/C compressor (1) for refrigerant oil. If refrigerant oil is found, the compressor shaft seal is leaking and the A/C compressor must be replaced.

Check the pulley bearing for roughness or excessive leakage of grease. Replace the pulley and bearing assembly, if required.