Dodge Nitro. Manual — part 730

inoperative A/C pressure
transducer.

Test the A/C pressure transducer and tighten
or replace as required.

6. Inoperative evaporator
temperature sensor.

6. See SENSOR-EVAPORATOR
TEMPERATURE . Test the evaporator
temperature sensor and replace as required.

7. Inoperative powertrain
control module (PCM) or
engine control module
(ECM), depending on
engine application.

7. Refer to the proper Diagnostic article for
testing of the PCM or ECM. Test the PCM or
ECM and replace as required.

Normal pressures, but A/C
Performance Test air
temperatures at center panel
outlet are too high.

1. Excessive refrigerant oil
in system.

1. See REFRIGERANT OIL LEVEL .
Recover the refrigerant from the refrigerant
system and inspect the refrigerant oil content.
Restore the refrigerant oil to the proper level
as required.

2. Blend door actuator
improperly installed or
inoperative.

2. See ACTUATOR-BLEND DOOR .
Inspect the actuator for proper operation and
replace as required.

3. Blend-air door
inoperative or sealing
improperly.

3. See HOUSING-HVAC . Inspect the blend-
air door for proper operation and sealing and
correct as required.

The low side pressure is
normal or slightly low, and
the high side pressure is too
low.

1. Low refrigerant system
charge.

1. See REFRIGERANT SYSTEM LEAKS .
Test the refrigerant system for leaks. Repair,
evacuate and charge the refrigerant system as
required.

2. Refrigerant flow through
the A/C accumulator is
restricted.

2. See EVAPORATOR-A/C . Replace the
restricted accumulator as required.

3. Refrigerant flow through
the A/C evaporator is
restricted.

3. See EVAPORATOR-A/C . Replace the
restricted A/C evaporator as required.

4. Inoperative A/C
compressor.

4. See COMPRESSOR-A/C . Replace the
A/C compressor as required.

The low side pressure is
normal or slightly high, and
the high side pressure is too
high.

1. A/C Condenser air flow
restricted.

1. Check the A/C condenser for damaged fins,
foreign objects obstructing air flow through
the condenser fins, and missing or improperly
installed air seals. Clean, repair, or replace
components as required.

2. Inoperative radiator
cooling fan.

2. Test the radiator cooling fan and replace as
required. Refer to Group 7.

3. Refrigerant system
overcharged.

3. See REFRIGERANT SYSTEM
CHARGE . Recover the refrigerant from the
refrigerant system. Charge the refrigerant
system to the proper level as required.

4. Air in the refrigerant

4. See REFRIGERANT SYSTEM LEAKS

2007 Dodge Nitro R/T

2007 HVAC Heating & Air Conditioning - Service Information - Nitro

HEATER PERFORMANCE

Before performing the following tests, refer to COOLING for the procedures to check the engine coolant level
and flow, engine coolant reserve/recovery system operation, accessory drive belt condition and tension, radiator
air flow and the fan drive operation.

If vehicle has been run recently, wait 15 minutes before removing the radiator cap. Place a rag over the cap and
turn it to the first safety stop. Allow pressure to escape through the overflow tube. When the system pressure
stabilizes, remove the cap completely.

MAXIMUM HEATER OUTPUT

Engine coolant is delivered to the heater core through two heater hoses. With the engine idling at normal
operating temperature, set the temperature control to the full hot position, the mode control to the floor position,
and the blower motor control to the highest speed position. Using a test thermometer, check the temperature of
the air being discharged at the front floor outlets. Compare the test thermometer reading to the Heater
Temperature Reference chart.

system.

to test the refrigerant system for leaks. Repair,
evacuate and charge the refrigerant system as
required.

5. Engine overheating.

5. Test the engine cooling system and repair, if
required. Refer to COOLING .

The low side pressure is too
high, and the high side
pressure is too low.

1. Accessory drive belt
slipping.

1. Inspect the accessory drive belt condition
and tension. Replace the accessory drive belt
and/or tensioner as required. Refer to
COOLING .

2. Inoperative A/C
expansion valve.

2. See VALVE-A/C EXPANSION . Test the
expansion valve and replace as required.

3. Inoperative A/C
compressor.

3. See COMPRESSOR-A/C . Replace the
A/C compressor as required.

The low side pressure is too
low, and the high side
pressure is too high.

1. Restricted refrigerant
flow through the refrigerant
lines.

1. See LINE-A/C LIQUID, LINE-A/C
SUCTION and LINE-A/C DISCHARGE.
Inspect the refrigerant lines for kinks, tight
bends or improper routing. Correct the routing
or replace the refrigerant line as required.

2. Restricted refrigerant
flow through the A/C
expansion valve.

2. See VALVE-A/C EXPANSION . Test the
expansion valve and replace as required.

3. Restricted refrigerant
flow through the A/C
condenser.

3. See CONDENSER-A/C . Replace the
restricted condenser as required.

WARNING:

Do not remove radiator cap when engine is hot, personal injury can result.

2007 Dodge Nitro R/T

2007 HVAC Heating & Air Conditioning - Service Information - Nitro

HEATER TEMPERATURE REFERENCE

If the heater outlet air temperature is below the minimum specification, refer to COOLING . 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 supply hose, locate and repair the engine coolant
flow obstruction in the cooling system (refer to COOLING for more information).

OBSTRUCTED COOLANT FLOW

Possible locations or causes of obstructed coolant flow are as follows:

Inoperative water pump.

Inoperative thermostat.

Pinched or kinked heater hoses.

Improper heater hose routing.

Plugged heater hoses or supply and return ports at the cooling system connections.

Plugged heater core.

If proper coolant flow through the cooling system is verified, and heater outlet air temperature is low, a
mechanical problem may exist.

MECHANICAL PROBLEMS

Possible causes of insufficient heat due to mechanical problems are as follows:

Obstructed cowl air intake.

Obstructed heater system outlets.

Inoperative engine thermostat.

Inoperative blower motor system.

Inoperative A/C-heater control.

Inoperative blend door actuator.

Inoperative, obstructed or improperly installed blend-air door.

TEMPERATURE CONTROL

If the heater outlet air temperature cannot be adjusted with the temperature control on the A/C-heater control,
the following could require service:

Inoperative A/C-heater control.

Inoperative blend door actuator.

Ambient Air Temperature

16°C

(60°F)

21°C

(70°F)

26°C

(80°F)

32°C

(90°F)

Minimum Air Temperature
at Floor Outlet

52°C

(125°F)

56°C

(133°F)

59°C

(139°F)

62°C

(144°F)

2007 Dodge Nitro R/T

2007 HVAC Heating & Air Conditioning - Service Information - Nitro

Inoperative, obstructed or improperly installed blend-air door.

Inoperative related wiring harness or connectors.

Improper engine coolant temperature.

SPECIFICATIONS

A/C SYSTEM

FASTENER TORQUE

Item

Description

Notes

A/C Compressor

Zexel DKS-17DS (2.8L/4.0L
engines)

VC-46 PAG oil

Visteon HS-18 (3.7L engine)

VC-46 PAG oil

Freeze-up Control

Evaporator temperature sensor

Input to A/C-heater control.
HVAC housing mounted.

Pressure Control

A/C pressure transducer

Input to PCM/ECM. A/C liquid
line mounted. Cycles clutch off if
refrigerant pressure falls below
206 kPa (30 psi) or rises above
2971 kPa (431 psi)

R-134a Refrigerant Charge
Capacity

0.510 kg (1.12 lbs.)

Also see A/C Underhood
Specification Label located in the
engine compartment.

A/C Clutch Coil Draw

3.3 amps @ 12V ± 0.5V @ 25°C
(77°F)

2.8L and 4.0L engines. A/C clutch
field coil resistance when
measured across coil lead
connector is 4.02 ± 0.2 ohms @
25°C (77°F).

3.1 - 4 amps @ 12V ± 0.5V @ 21°
C (70°F)

3.7L engine.

A/C Clutch Air Gap

0.30 - 0.60 mm (0.012 - 0.024 in.) 2.8L and 4.0L engines.
0.35 - 0.65 mm (0.014 - 0.025 in.) 3.7L engine.

Description

N.m

Ft. Lbs.

In. Lbs.

All Screws NOT Listed
Below

1.2

-

10

A/C Compressor Bolts
(2.8L and 4.0L Engines)

28

21

-

A/C Compressor Rear
Bolts (3.7L Engine)

55

-

41

A/C Compressor Front
Inboard Bolt (3.7L
Engine)

40

-

30

2007 Dodge Nitro R/T

2007 HVAC Heating & Air Conditioning - Service Information - Nitro