Automatic Air Conditioner: Other Nissan Altima L31

Precautions for Supplemental Restraint System (SRS) "AIR BAG" and "SEAT BELT PRETENSIONER"

The Supplemental Restraint System such as "AIR BAG" and "SEAT BELT PRETENSIONER", used along with a front seat belt, helps to reduce the risk or severity of injury to the driver and front passenger for certain types of collision. Information necessary to service the system safely is included in the SRS and SB section of this Service Manual.

Precautions for Working with HFC-134a (R-134a)

Contaminated Refrigerant

If a refrigerant other than pure R-134a is identified in a vehicle, your options are

1. Explain to the customer that environmental regulations prohibit the release of contaminated refrigerant into the atmosphere.
2. Explain that recovery of the contaminated refrigerant could damage your service equipment and refrigerant supply.
3. Suggest the customer return the vehicle to the location of previous service where the contamination may have occurred.
4. If you choose to perform the repair, recover the refrigerant using only dedicated equipment and containers. Do not recover contaminated refrigerant into your existing service equipment. If your facility does not have dedicated recovery equipment, you may contact a local refrigerant product retailer for available service. This refrigerant must be disposed of in accordance with all federal and local regulations. In addition, replacement of all refrigerant system components on the vehicle is recommended.
5. If the vehicle is within the warranty period, the air conditioner warranty is void. Please contact Nissan Customer Affairs for further assistance.

General Refrigerant Precautions

Precautions for Leak Detection Dye

1. The A/C system contains a fluorescent leak detection dye used for locating refrigerant leaks. An ultraviolet (UV) lamp is required to illuminate the dye when inspecting for leaks.
2. Always wear fluorescence enhancing UV safety glasses to protect your eyes and enhance the visibility of the fluorescent dye.
3. A compressor shaft seal should not be repaired because of dye seepage. The compressor shaft seal should only be repaired after confirming the leak with an electronic refrigerant leak detector (J-41995).
4. Always remove any dye from the leak area after repairs are complete to avoid a misdiagnosis during a future service.
5. Do not allow dye to come into contact with painted body panels or interior components. If dye is spilled, clean immediately with the approved dye cleaner. Fluorescent dye left on a surface for an extended period of time CANNOT BE REMOVED .
6. Do not spray the fluorescent dye cleaning agent on hot surfaces (engine exhaust manifold, etc.).
7. Do not use more than one refrigerant dye bottle (1/4 ounce / 7.4 cc) per A/C system.
8. Leak detection dyes for R-134a and R-12 A/C systems are different. Do not use R-134a leak detection dye in R-12 A/C systems or R-12 leak detection dye in R-134a A/C systems or A/C system damage may result.
9. The fluorescent properties of the dye will remain for over three (3) years unless a compressor failure occurs.

Precautions for Refrigerant Connection

A new type refrigerant connection has been introduced to all refrigerant lines except the following locations.

1. Expansion valve to cooling unit
2. Evaporator pipes to evaporator (inside cooling unit)
3. Refrigerant pressure sensor

Scheme 180

1. The O-ring has been relocated. It has also been provided with a groove for proper installation. This eliminates the chance of the O-ring being caught in, or damaged by, the mating part. The sealing direction of the O-ring is now set vertically in relation to the contacting surface of the mating part to improve sealing characteristics.
2. The reaction force of the O-ring will not occur in the direction that causes the joint to pull out, thereby facilitating piping connections.

Scheme 181

Scheme 182

Scheme 183

Precautions for Servicing Compressor

1. Plug all openings to prevent moisture and foreign matter from entering.
2. When the compressor is removed, store it in the same position as it is when mounted on the car.
3. When replacing or repairing compressor, follow "Maintenance of Lubricant Quantity in Compressor" exactly. Refer to «MAINTENANCE OF LUBRICANT QUANTITY IN COMPRESSOR»(ref-206580-S25557481852005112500000) .
4. Keep friction surfaces between clutch and pulley clean. If the surface is contaminated, with lubricant, wipe it off by using a clean waste cloth moistened with thinner.
5. After compressor service operation, turn the compressor shaft by hand more than 5 turns in both directions. This will equally distribute lubricant inside the compressor. After the compressor is installed, let the engine idle and operate the compressor for 1 hour.
6. After replacing the compressor magnet clutch, apply voltage to the new one and check for normal operation. [Gap between clutch disc and pulley is 0.3 - 0.6 mm (0.012 - 0.024 in)]

RECOVERY/RECYCLING EQUIPMENT

Follow the manufacturer's instructions for machine operation and machine maintenance. Never introduce any refrigerant other than that specified into the machine.

ELECTRONIC LEAK DETECTOR

Follow the manufacturer's instructions for tester operation and tester maintenance.

VACUUM PUMP

The lubricant contained inside the vacuum pump is not compatible with the specified lubricant for HFC-134a (R-134a) A/C systems. The vent side of the vacuum pump is exposed to atmospheric pressure so the vacuum pump lubricant may migrate out of the pump into the service hose. This is possible when the pump is switched off after evacuation (vacuuming) and hose is connected to it.

To prevent this migration, use a manual valve situated near the hose-to-pump connection, as follows.

1. Usually vacuum pumps have a manual isolator valve as part of the pump. Close this valve to isolate the service hose from the pump.
2. For pumps without an isolator, use a hose equipped with a manual shut-off valve near the pump end. Close the valve to isolate the hose from the pump.
3. If the hose has an automatic shut off valve, disconnect the hose from the pump: as long as the hose is connected, the valve is open and lubricating oil may migrate.

Some one-way valves open when vacuum is applied and close under a no vacuum condition. Such valves may restrict the pump's ability to pull a deep vacuum and are not recommended.

Scheme 184

MANIFOLD GAUGE SET

Be certain that the gauge face indicates R-134a or 134a. Make sure the gauge set has 1/2"-16 ACME threaded connections for service hoses. Confirm the set has been used only with refrigerant HFC-134a (R-134a) along with specified lubricant.

Scheme 185

SERVICE HOSES

Be certain that the service hoses display the markings described (colored hose with black stripe). All hoses must include positive shut-off devices (either manual or automatic) near the end of the hoses opposite the manifold gauge.

Scheme 186

SERVICE COUPLERS

Never attempt to connect HFC-134a (R-134a) service couplers to a CFC-12 (R-12) A/C system. The HFC-134a (R-134a) couplers will not properly connect to the CFC-12 (R-12) system. However, if an improper connection is attempted, discharging and contamination may occur.

Scheme 187

Scheme 188

REFRIGERANT WEIGHT SCALE

Verify that no refrigerant other than HFC-134a (R-134a) and specified lubricants have been used with the scale. If the scale controls refrigerant flow electronically, the hose fitting must be 1/2"-16 ACME.

Scheme 189

CHARGING CYLINDER

Using a charging cylinder is not recommended. Refrigerant may be vented into air from cylinder's top valve when filling the cylinder with refrigerant. Also, the accuracy of the cylinder is generally less than that of an electronic scale or of quality recycle/recharge equipment.

Special Service Tools

The actual shapes of Kent-Moore tools may differ from those of special service tools illustrated here.

Scheme 190

HFC-134a (R-134a) Service Tools and Equipment

Never mix HFC-134a refrigerant and/or its specified lubricant with CFC-12 (R-12) refrigerant and/or its lubricant.

Separate and non-interchangeable service equipment must be used for handling each type of refrigerant/lubricant.

Refrigerant container fittings, service hose fittings and service equipment fittings (equipment which handles refrigerant and/or lubricant) are different between CFC-12 (R-12) and HFC-134a (R-134a). This is to avoid mixed use of the refrigerants/lubricant.

Adapters that convert one size fitting to another must never be used: refrigerant/lubricant contamination will occur and compressor failure will result.

Scheme 191

Scheme 192

Scheme 193

Scheme 194

Scheme 195

REFRIGERANT FLOW

The refrigerant flows in the standard pattern, that is, through the compressor, the condenser with liquid tank, through the evaporator, and back to the compressor. The refrigerant evaporation through the evaporator coil is controlled by an externally equalized expansion valve, located inside the evaporator case.

FREEZE PROTECTION

Under normal operating conditions, when the A/C is switched on the compressor runs continuously, and the evaporator pressure and temperature are controlled by the compressor to prevent freeze up.

REFRIGERANT PRESSURE SENSOR

The refrigerant system is protected against excessively high or low pressures by the refrigerant pressure sensor, located on the liquid tank. If the system pressure rises above or falls below the specifications, the refrigerant pressure sensor detects the pressure inside the refrigerant line and sends the voltage signal to the ECM. ECM makes the A/C relay go OFF and stops the compressor when pressure on the high pressure side detected by refrigerant pressure sensor is over about 2,746 kPa (28 kg/cm 2 , 398 psi), or below about 120 kPa (1.22 kg/cm 2 , 17.4 psi).

PRESSURE RELIEF VALVE

The refrigerant system is also protected by a pressure relief valve, located in the rear head of the compressor. When the pressure of refrigerant in the system increases to an abnormal level [more than 3,727 kPa (38 kg/cm 2 , 540 psi)], the release port on the pressure relief valve automatically opens and releases refrigerant into the atmosphere.

Scheme 196

Scheme 197

LUBRICANT

Name: Nissan A/C System Oil Type DH-PS

Part number: KLH00-PAGS0

CHECKING AND ADJUSTING

Adjust the lubricant quantity according to the test group shown below.

1. LUBRICANT RETURN OPERATION Can lubricant return operation be performed? A/C system works properly. There is no evidence of a large amount of lubricant leakage. Yes or No Yes: GO TO 2. No: GO TO 3 .
2. PERFORM LUBRICANT RETURN OPERATION, PROCEEDING AS FOLLOWS Start engine, and set the following conditions: Test condition Engine speed: Idling to 1,200 rpm A/C switch: ON Blower speed: Max. position Temp. control: Optional [Set so that intake air temperature is 25 to 30°C (77 to 86°F).] Intake position: Recirculation (REC) Perform lubricant return operation for about 10 minutes. Stop engine. CAUTION: If excessive lubricant leakage is noted, do not perform the lubricant return operation. : GO TO 3.
3. CHECK COMPRESSOR Should the compressor be replaced? Yes or No Yes: GO TO «LUBRICANT ADJUSTMENT PROCEDURE FOR COMPRESSOR REPLACEMENT»(ref-206580-S10893574602005112500000) . No: GO TO 4.
4. CHECK ANY PART Is there any part to be replaced? (Evaporator, condenser, liquid tank or in case there is evidence of a large amount of lubricant leakage.) Yes or No Yes: GO TO «LUBRICANT ADJUSTING PROCEDURE FOR COMPONENTS REPLACEMENT EXCEPT COMPRESSOR»(ref-206580-S10893574602005112500000) . No: Carry out the A/C performance test.

System Construction

A small network is constructed between the auto amplifier, air mix door motor and mode door motor. The auto amplifier and motors are connected by data transmission lines and motor power supply lines. The LAN network is built through the ground circuits of the two motors.

Addresses, motor opening angle signals, motor stop signals and error checking messages are all transmitted through the data transmission lines connecting the auto amplifier and two motors.

The following functions are contained in LCUs built into the air mix door motor and the mode door motor.

Scheme 198

1. Address
2. Motor opening angle signals
3. Data transmission
4. Motor stop and drive decision
5. Opening angle sensor (PBR function)
6. Comparison
7. Decision (Auto amplifier indicated value and motor opening angle comparison)

TRANSMISSION DATA AND TRANSMISSION ORDER

Amplifier data is transmitted consecutively to each of the door motors following the form shown in figure below.

Start: Initial compulsory signal sent to each of the door motors.

Address: Data sent from the auto amplifier is selected according to data-based decisions made by the air mix door motor, mode door motor and intake door motor.

If the addresses are identical, the opening angle data and error check signals are received by the door motor LCUs. The LCUs then make the appropriate error decision. If the opening angle data is normal, door control begins.

If an error exists, the received data is rejected and corrected data received. Finally, door control is based upon the corrected opening angle data.

Opening angle: Data that shows the indicated door opening angle of each door motor.

Error check: Procedure by which sent and received data is checked for errors. Error data is then compiled. The error check prevents corrupted data from being used by the air mix door motor, mode door motor and intake door motor. Error data can be related to the following problems.

1. Abnormal electrical frequency
2. Poor electrical connections
3. Signal leakage from transmission lines
4. Signal level fluctuation

Stop signal: At the end of each transmission, a stop operation, in-operation, or internal problem message is delivered to the auto amplifier. This completes one data transmission and control cycle.

Scheme 199

AIR MIX DOOR CONTROL (AUTOMATIC TEMPERATURE CONTROL)

The air mix door is automatically controlled so that in-vehicle temperature is maintained at a predetermined value by: The temperature setting, ambient temperature, in-vehicle temperature and amount of sunload.

FAN SPEED CONTROL

Blower speed is automatically controlled based on temperature setting, ambient temperature, in-vehicle temperature, intake temperature, amount of sunload and air mix door position.

With FAN switch set to AUTO, the blower motor starts to gradually increase air flow volume.

When engine coolant temperature is low, the blower motor operation is delayed to prevent cool air from flowing.

INTAKE DOOR CONTROL

The intake doors are automatically controlled by the: temperature setting, ambient temperature, in-vehicle temperature, intake temperature, amount of sunload and ON-OFF operation of the compressor.

OUTLET DOOR CONTROL

The outlet door is automatically controlled by the: temperature setting, ambient temperature, in-vehicle temperature, intake temperature and amount of sunload.

MAGNET CLUTCH CONTROL

The ECM controls compressor operation using input signals from the throttle position sensor and auto amplifier.

DISPLAY SCREEN

Displays the operational status of the system.

AUTO SWITCH

The compressor, intake doors, air mix door, outlet doors and blower speed are automatically controlled so that the in-vehicle temperature will reach, and be maintained at the set temperature selected by the operator.

ECON (ECONOMY) SWITCH

By pressing the ECON switch, the display screen should indicate ECON and the compressor always turns OFF. With the compressor OFF, the system will not remove heat (cool) or de-humidify. The system will maintain the in-vehicle temperature at the set temperature when the set the temperature is above the ambient (outside) temperature. The system will set the intake doors to the outside air position.

TEMPERATURE DIAL (POTENTIAL TEMPERATURE CONTROL)

Increases or decreases the set temperature.

OFF SWITCH

The compressor and blower are OFF, the intake doors are set to the outside air position, and the air outlet doors are set to the foot (80% foot and 20% defrost) position.

FAN SWITCH

Manually controls the blower speed. Five speeds are available for manual control (as shown on the display screen).

RECIRCULATION (REC) SWITCH

OFF position: Outside air is drawn into the passenger compartment.

ON position: Interior air is recirculated inside the vehicle.

DEFROSTER (DEF) SWITCH

Positions the air outlet doors to the defrost position. Also positions the intake doors to the outside air position.

MODE SWITCH

Controls the air discharge outlets.

REAR WINDOW DEFOGGER SWITCH

This switch turns the rear window defogger ON and OFF.

Scheme 200

Scheme 201

Scheme 202

Unconfirmed Incidents

The customer may feel that the cabin temperature is not being controlled or regulated to the temperature indicated by the auto A/C display screen. To satisfy individual driver preference the Temperature Setting Trimmer may be used to compensate in a range of +/-3°C (+/-6°F).

1. Enter Self Diagnosis mode and select STEP 5.
2. Press the Fan Up switch: This will set the A/C system in auxiliary mode and the display will show 61.
3. Turn the temperature dial clockwise or counterclockwise: The temperature will change at a rate of 0.5°C (1°F).

If power is lost to the A/C Auto Amp., trimmer setting is canceled and setting becomes that of initial condition

Scheme 203

When battery cable is disconnected, trimmer operation is canceled. Temperature set becomes that of initial condition, i.e. 0°C (0°F).

CONDITIONS

1. Engine running and at normal operating temperature.

Scheme 204

Scheme 205

Scheme 206

Scheme 207

Scheme 208

Scheme 209

Scheme 210

Scheme 211

Scheme 212

1. Check Memory Function Set the temperature 90°F or 32°C. Press OFF switch. Turn the ignition off. Turn the ignition on. Press the AUTO switch. Confirm that the set temperature remains at previous temperature. Press OFF switch. If NG, go to «MEMORY FUNCTION»(ref-206580-S39631818512005112500000) . If OK, continue with next check.
2. Check Blower Press fan switch (up side) one time. Blower should operate on low speed. The fan symbol should have one bar lit. Press fan switch (up side) one more time, and continue checking blower speed and fan symbol until all speeds are checked. Leave blower on MAX speed. If NG, go to «BLOWER MOTOR CIRCUIT»(ref-206580-S13397563942005112500000) . If OK, continue with next check.
3. Check Discharge Air Press mode switch four times and DEF button. Each position indicator should change shape. Confirm that discharge air comes out according to the air distribution table. Refer to «DISCHARGE AIR FLOW»(ref-206580-S01572091342005112500000) . NOTE: Confirm that the compressor clutch is engaged (visual inspection) and intake door position is at FRESH when the DEF is selected. Intake door position is checked in the next step. If NG, go to «MODE DOOR MOTOR CIRCUIT»(ref-206580-S18651121222005112500000) . If OK, continue with next check.
4. Check Recirculation Press REC switch. Recirculation indicator should illuminate. Listen for intake door position change (you should hear blower sound change slightly). If NG, go to «INTAKE DOOR MOTOR CIRCUIT»(ref-206580-S38631518982005112500000) . If OK, continue with next check.
5. Check Temperature Decrease Turn the temperature dial counterclockwise until 18°C (60°F) is displayed. Check for cold air at discharge air outlets. If NG, go to «INSUFFICIENT COOLING»(ref-206580-S27546083642005112500000) . If OK, continue with next check.
6. Check Temperature Increase Turn the temperature dial clockwise until 32°C (90°F) is displayed. Check for hot air at discharge air outlets. If NG, go to «INSUFFICIENT HEATING»(ref-206580-S34109480762005112500000) . If OK, continue with next check.
7. Check ECON (Economy) Mode Set the temperature 25°C (75°F). Press ECON switch. Display should indicate ECON (no AUTO). Confirm that the compressor clutch is not engaged (visual inspection). (Discharge air and blower speed will depend on ambient, in-vehicle and set temperatures.) If NG, go to «ECON (ECONOMY) MODE»(ref-206580-S10798132442005112500000) . If OK, continue with next check.
8. Check AUTO Mode Press AUTO switch. Display should indicate AUTO (no ECON). Confirm that the compressor clutch engages (audio or visual inspection). (Discharge air and blower speed will depend on ambient, in-vehicle and set temperatures.) If NG, go to «DIAGNOSTIC PROCEDURE»(ref-206580-S08507777942005112500000) , then if necessary, «MAGNET CLUTCH CIRCUIT»(ref-206580-S27395998002005112500000) . If all operational check are OK (symptom can not be duplicated), go to «HOW TO PERFORM EFFICIENT DIAGNOSIS FOR AN ELECTRICAL INCIDENT»(ref-206580-S38401363872005112500000) and perform tests as outlined to simulate driving conditions environment. If symptom appears, refer to «SYMPTOM TABLE»(ref-206580-S34537490302005112500000) and perform applicable trouble diagnosis procedures.

Power Supply and Ground Circuit for Auto Amp.

SYMPTOM

1. A/C system does not come on.

Scheme 213

AUTOMATIC AMPLIFIER (AUTO AMP.)

The auto amplifier has a built-in microcomputer which processes information sent from various sensors needed for air conditioner operation. The air mix door motor, mode door motor, intake door motor, blower motor and compressor are then controlled.

The auto amplifier is unitized with control mechanisms. Signals from various switches and Potential Temperature Control (PTC) are directly entered into auto amplifier.

Self-diagnostic functions are also built into auto amplifier to provide quick check of malfunctions in the auto air conditioner system.

Scheme 214

POTENTIAL TEMPERATURE CONTROL (PTC)

The PTC is built into the A/C auto amp. It can be set at an interval of 0.5°C (1.0°F) in the 18°C (60°F) to 32°C (90°F) temperature range by pushing the temperature button. The set temperature is digitally displayed.

Scheme 215

LAN System Circuit

SYMPTOM: Mode door motor, intake door motor and/or air mix door motor does not operate normally.

Scheme 216

Scheme 217

Scheme 218

Scheme 219

Scheme 220

Scheme 221

Scheme 222

Scheme 223

Scheme 224

Scheme 225

Scheme 226

1. CHECK POWER SUPPLY FOR AUTO AMP. (LCU) SIDE OK or NG OK: GO TO 2. NG: Replace auto amp.(LCU).
2. CHECK SIGNAL FOR AUTO AMP. (LCU) SIDE OK or NG OK: GO TO 3. NG: Replace auto amp.(LCU).
3. CHECK POWER SUPPLY FOR MOTOR SIDE OK or NG OK: GO TO 4. NG: Replace harness or connector.
4. CHECK SIGNAL FOR MOTOR SIDE OK or NG OK: GO TO 5. NG: Replace harness or connector.
5. CHECK MOTOR GROUND CIRCUIT OK or NG OK: GO TO 6. NG: Replace harness or connector.
6. CHECK MOTOR OPERATION Disconnect and reconnect the motor connectors and confirm the motor operation. OK or NG OK: (Return to operate normally.) Poor contacting the motor connector NG: (Does not operate normally.) : GO TO 7.
7. CHECK MODE DOOR MOTOR AND AIR MIX DOOR MOTOR OPERATION Disconnect the intake door motor connector. Reconnect the mode door motor connector and air mix door motor connector, confirm the mode door motor and air mix door motor operation. OK or NG OK: (Mode door motor and air mix door motor operate normally.) Replace the intake door motor. NG: (Mode door motor and air mix door motor do not operate normally.) : GO TO 8.
8. CHECK AIR MIX DOOR MOTOR AND INTAKE DOOR MOTOR OPERATION Disconnect mode door motor connector. Reconnect the intake door motor connector, confirm the air mix door motor and intake door motor operation. OK or NG OK: (Air mix door motor and intake door motor operate normally.) Replace mode door motor. NG: (Air mix door motor and intake door motor do not operate normally.) : GO TO 9.
9. CHECK INTAKE DOOR MOTOR AND MODE DOOR MOTOR OPERATION Disconnect air mix door motor connector. Reconnect mode door motor connector, confirm the intake door motor and mode door motor operation. OK or NG OK: (Intake door motor and mode door motor operate normally.) Replace air mix door motor. NG: (Intake door motor and mode door motor do not operate normally.) Replace auto amp.

Mode Door Motor Circuit

SYMPTOM

1. Air outlet does not change.
2. Mode door motor does not operate normally.

Scheme 227

Component Parts

Mode door control system components are

1. Auto amp.
2. Mode door motor (LCU)
3. In-vehicle sensor
4. Ambient sensor
5. Sunload sensor
6. Intake sensor

Air Mix Door Motor Circuit

SYMPTOM

1. Discharge air temperature does not change.
2. Air mix door motor does not operate.

Scheme 228

Air mix door control system components are

1. Auto amp.
2. Air mix door motor (LCU)
3. In-vehicle sensor
4. Ambient sensor
5. Sunload sensor
6. Intake sensor

Air Mix Door Motor

The air mix door motor is attached to the heater and cooling unit. It rotates so that the air mix door is opened or closed to a position set by the auto amplifier. Motor rotation is then conveyed through a shaft and the air mix door position is then fed back to the auto amplifier by PBR built-in air mix door motor.

Scheme 229

Intake Door Motor Circuit

SYMPTOM

1. Intake door does not change.
2. Intake door motor does not operate normally.

Scheme 230

Intake door control system components are

1. Auto amp.
2. Intake door motor
3. A/C LAN system (PBR built-in mode motor and air mix door motor)
4. In-vehicle sensor
5. Ambient sensor
6. Sunload sensor
7. Intake sensor

Blower Motor Circuit

SYMPTOM

1. Blower motor operation is malfunctioning.

Scheme 231

Fan speed control system components are

1. Auto amp.
2. A/C LAN system (PBR built-in mode door motor, air mix door motor and intake door motor)
3. In-vehicle sensor
4. Ambient sensor
5. Sunload sensor
6. Intake sensor

Scheme 232

Automatic Mode

In the automatic mode, the blower motor speed is calculated by the automatic amplifier based on inputs from the PBR, in-vehicle sensor, sunload sensor, intake sensor and ambient sensor.

When the air flow is increased, the duty ratio of the blower fan motor's drive signal is changed at 8% sec. to prevent a sudden increase in air flow.

In addition to manual air flow control and the normal automatic air flow control, starting air flow control, low water temperature starting control and high passenger compartment temperature starting control are available.

Starting Fan Speed Control

Start Up From COLD SOAK Condition (Automatic mode)

In a cold start up condition where the engine coolant temperature is below 56°C (133°F), the blower will not operate for a short period of time (up to 150 seconds). The exact start delay time varies depending on the ambient and engine coolant temperature.

In the most extreme case (very low ambient) the blower starting delay will be 150 seconds as described above. After this delay, the blower will operate at low speed until the engine coolant temperature rises above 56°C (133°F), at which time the blower speed will increase to the objective speed.

Start Up From Normal or HOT SOAK Condition (Automatic mode)

The blower will begin operation momentarily after the A/C button is pushed. The blower speed will gradually rise to the objective speed over a time period of 3 seconds or less (actual time depends on the objective blower speed).

Blower Speed Compensation

Sunload

When the in-vehicle temperature and the set temperature are very close, the blower will be operating at low speed. The low speed will vary depending on the sunload. During conditions of high sunload, the blower low speed is "normal" low speed (approx. 6V). During low or no sunload conditions, the low speed will drop to "low" low speed (approx. 5V).

Scheme 233

Fan Control Amplifier

The fan control amplifier is located on the cooling unit. The fan control amp. receives a gate voltage from the auto amp. to smoothly maintain the blower fan motor voltage in the 5 to the 12V range (approx.).

Scheme 234

Blower Motor

Confirm smooth rotation of the blower motor.

Scheme 235

1. Ensure that there are no foreign particles inside the intake unit.

Fan Control Amp.

Check continuity between terminals.

Scheme 236

Scheme 237

Magnet Clutch Circuit

SYMPTOM: Magnet clutch does not engage.

Scheme 238

Low Temperature Protection Control

Auto amp. will turn the compressor ON or OFF as determined by a signal detected by ambient sensor.

When ambient temperatures are greater than -2°C (28°F), the compressor turns ON. The compressor turns OFF when ambient temperatures are less than -5°C (23°F).

Scheme 239

The refrigerant pressure sensor is attached to the condenser.

Scheme 240

Scheme 241

Scheme 242

Scheme 243

1. Run engine and operate A/C system.
2. Connect the voltmeter from harness side.
3. Check the thermo control amp. operation as shown in the table.

Insufficient Cooling

SYMPTOM: Insufficient cooling

Scheme 244

Scheme 245

Scheme 246

Insufficient Heating

SYMPTOM: Insufficient heating

Scheme 247

Memory Function

SYMPTOM: Memory function does not operate.

Scheme 248

ECON (ECONOMY) Mode

SYMPTOM: ECON mode does not operate.

Scheme 249

Ambient Sensor

The ambient sensor is attached to the front bumper reinforcement. It detects ambient temperature and converts it into a resistance value which is then input into the auto amplifier.

Scheme 250

AMBIENT TEMPERATURE INPUT PROCESS

The automatic amplifier includes a processing circuit for the ambient sensor input. However, when the temperature detected by the ambient sensor increases quickly, the processing circuit retards the auto amp. function. It only allows the auto amp. to recognize an ambient temperature increase of 0.33°C (0.6°F) per 100 seconds. As an example, consider stopping for a cup of coffee after high speed driving. Although the actual ambient temperature has not changed, the temperature detected by the ambient sensor will increase. This is because the heat from the engine compartment can radiate to the front grille area, location of the ambient sensor.

After disconnecting ambient sensor harness connector, measure resistance between terminals 2 and 1 at sensor harness side, using the table below.

Scheme 251

Scheme 252

If NG, replace ambient sensor.

In-vehicle sensor

The in-vehicle sensor is located on instrument lower panel. It converts variations in temperature of compartment air drawn from the aspirator into a resistance value. It is then input into the auto amplifier.

Scheme 253

Aspirator

The aspirator is located on driver's side of heater and cooling unit. It produces vacuum pressure due to air discharged from the heater and cooling unit, continuously taking compartment air in the aspirator.

Scheme 254

Scheme 255

After disconnecting in-vehicle sensor harness connector, measure resistance between terminals 1 and 2 at sensor harness side, using the table below.

Scheme 256

Scheme 257

If NG, replace in-vehicle sensor.

SUNLOAD INPUT PROCESS

The auto amp. also includes a processing circuit which average the variations in detected sunload over a period of time. This prevents drastic swings in the ATC system operation due to small or quick variations in detected sunload.

For example, consider driving along a road bordered by an occasional group of large trees. The sunload detected by the sunload sensor will vary whenever the trees obstruct the sunlight. The processing circuit averages the detected sunload over a period of time, so that the (insignificant) effect of the trees momentarily obstructing the sunlight does not cause any change in the ATC system operation. On the other hand, shortly after entering a long tunnel, the system will recognize the change in sunload, and the system will react accordingly.

Sunload Sensor

Measure voltage between auto amp. terminal 12 and body ground. If NG, replace auto amp.

Scheme 258

Scheme 259

1. When checking sunload sensor, select a place where sun shines directly on it.

Intake Sensor

The intake sensor is located on the heater and cooling unit. It converts temperature of air after it passes through the evaporator into a resistance value which is then input to the auto amp.

After disconnecting intake sensor harness connector, measure resistance between terminals 1 and 2 at sensor harness side, using the table below.

Scheme 260

Scheme 261

If NG, replace intake sensor.

Discharging Refrigerant

Scheme 262

Scheme 263

Scheme 264

Components

Refer to PRECAUTIONS FOR REFRIGERANT CONNECTION .

Scheme 265

Scheme 266

Pulley

Check the appearance of the pulley assembly. If contact surface of pulley shows signs of excessive grooving, replace clutch disc and pulley. The contact surfaces of the pulley assembly should be cleaned with a suitable solvent before reinstallation.

Coil

Check magnet coil for loose connection or cracked insulation.

Scheme 267

Scheme 268

Scheme 269

Scheme 270

Scheme 271

1. Install the magnet coil. Be sure to align the magnet coil pin with the hole in the compressor front head.
2. Install the magnet coil harness clip using a screwdriver.
3. Install the pulley assembly using the installer and a wrench, and then install the snap ring using snap ring pliers.
4. Install the clutch disc on the drive shaft, together with the original shim(s). Press the clutch disc down by hand.
5. Using the clutch disc tool to prevent clutch disc rotation, tighten the bolt to 12 N.m (1.2 kg-m, 9 ft-lb).
6. After tightening the bolt, check that the pulley rotates smoothly.
7. Check clearance all the way around the clutch disc. Clutch disc-to-pulley: 0.3 - 0.6 mm (0.012 - 0.024 in) clearance If the specified clearance is not obtained, replace adjusting spacer and readjust.

Checking for Refrigerant Leaks

Perform a visual inspection of all refrigeration parts, fittings, hoses and components for signs of A/C lubricant leakage, damage and corrosion. A/C lubricant leakage may indicate an area of refrigerant leakage. Allow extra inspection time in these areas when using either an electronic refrigerant leak detector or fluorescent dye leak detector.

If dye is observed, confirm the leak with an electronic refrigerant leak detector. It is possible a prior leak was repaired and not properly cleaned.

When searching for leaks, do not stop when one leak is found but continue to check for additional leaks at all system components and connections.

When searching for refrigerant leaks using an electronic leak detector, move the probe along the suspected leak area at 25 - 50 mm (1 - 2 in) per second and no further than 6 mm (1/4 in) from the component.

Checking System for Leaks Using the Fluorescent Leak Detector

1. Check A/C system for leaks using the UV lamp and safety glasses (J-42220) in a low sunlight area (area without windows preferable). Illuminate all components, fittings and lines. The dye will appear as a bright green/yellow area at the point of leakage. Fluorescent dye observed at the evaporator drain opening indicates an evaporator core assembly (tubes, core or TXV) leak.
2. If the suspected area is difficult to see, use an adjustable mirror or wipe the area with a clean shop rag or cloth, with the UV lamp for dye residue.
3. After the leak is repaired, remove any residual dye using dye cleaner (J-43872) to prevent future misdiagnosis.
4. Perform a system performance check and verify the leak repair with an approved electronic refrigerant leak detector. NOTE: Other gases in the work area or substances on the A/C components, for example, anti-freeze, windshield washer fluid, solvents and lubricants, may falsely trigger the leak detector. Make sure the surfaces to be checked are clean. Clean with a dry cloth or blow off with shop air. Do not allow the sensor tip of the detector to contact with any substance. This can also cause false readings and may damage the detector.

Dye Injection

(This procedure is only necessary when recharging the system or when the compressor has seized and was replaced.)

1. Check A/C system static (at rest) pressure. Pressure must be at least 345 kPa (50 psi).
2. Pour one bottle (1/4 ounce / 7.4 cc) of the A/C refrigerant dye into the injector tool (J-41459).
3. Connect the injector tool to the A/C LOW PRESSURE side service fitting.
4. Start engine and switch A/C ON.
5. When the A/C operating (compressor running), inject one bottle (1/4 ounce / 7.4 cc) of fluorescent dye through the low-pressure service valve using dye injector tool J-41459 (refer to the manufacturer's operating instructions).
6. With the engine still running, disconnect the injector tool from the service fitting. CAUTION: Be careful the A/C system or replacing a component, pour the dye directly into the open system connection and proceed with the service procedures.
7. Operate the A/C system for a minimum of 20 minutes to mix the dye with the system oil. Depending on the leak size, operating conditions and location of the leak, it may take from minutes to days for the dye to penetrate a leak and become visible.

PRECAUTIONS FOR HANDLING LEAK DETECTOR

When performing a refrigerant leak check, use a J-41995 A/C leak detector or equivalent. Ensure that the instrument is calibrated and set properly per the operating instructions.

The leak detector is a delicate device. In order to use the leak detector properly, read the operating instructions and perform any specified maintenance.

Scheme 272

Scheme 273

Scheme 274

Scheme 275

1. Position probe approximately 5 mm (3/16 in) away from point to be checked.
2. When testing, circle each fitting completely with probe.
3. Move probe along component approximately 25 to 50 mm (1 to 2 in)/sec.

CHECKING PROCEDURE

To prevent inaccurate or false readings, make sure there is no refrigerant vapor, shop chemicals, or cigarette smoke in the vicinity of the vehicle. Perform the leak test in calm area (low air/wind movement) so that the leaking refrigerant is not dispersed.

Scheme 276

1. Turn engine OFF.
2. Connect a suitable A/C manifold gauge set to the A/C service ports.
3. Check if the A/C refrigerant pressure is at least 345 kPa (3.52 kg/cm 2 , 50 psi) above 16°C (61°F). If less than specification, recover/evacuate and recharge the system with the specified amount of refrigerant. NOTE: At temperatures below 16°C (61°F), leaks may not be detected since the system may not reach 345 kPa (3.54 kg/cm 2 , 50 psi).
4. Conduct the leak test from the high side (compressor discharge a to evaporator inlet f) to the low side (evaporator drain hose g to shaft seal I). Refer to «COMPONENTS»(ref-206580-S14008217572005112500000) . Perform a leak check for the following areas carefully. Clean the component to be checked and move the leak detected probe completely around the connection/component. Compressor Check the fitting of high- and low-pressure hoses, relief valve and shaft seal. Liquid tank Check the refrigerant pressure sensor. Service valves Check all around the service valves. Ensure service valve caps are secured on the service valves (to prevent leaks). NOTE: After removing A/C manifold gauge set from service valves, wipe any residue from valves to prevent any false readings by leak detector. Cooling unit (Evaporator) With engine OFF, turn blower fan on "High" for at least 15 seconds to dissipate any refrigerant trace in the cooling unit. Wait a minimum of 10 minutes accumulation time (refer to the manufacturer's recommended procedure for actual wait time) before inserting the leak detector probe into the drain hose. Keep the probe inserted for at least 10 seconds. Use caution not to contaminate the probe tip with water or dirt that may be in the drain hose.
5. If a leak detector detects a leak, verify at least once by blowing compressed air into area of suspected leak, then repeat check as outlined above.
6. Do not stop when one leak is found. Continue to check for additional leaks at all system components. If no leaks are found, perform steps 7 - 10.
7. Start engine.
8. Set the heater A/C control as follows; A/C switch: ON Face mode Intake position: Recirculation Max cold temperature Fan speed: High
9. Run engine at 1,500 rpm for at least 2 minutes.
10. Turn engine off and perform leak check again following steps 4 through 6 above. Refrigerant leaks should be checked immediately after stopping the engine. Begin with the leak detector at the compressor. The pressure on the high pressure side will gradually drop after refrigerant circulation stops and pressure on the low pressure side will gradually rise, as shown in the graph. Some leaks are more easily detected when pressure is high.
11. Before connecting ACR4 to vehicle, check ACR4 gauges. No refrigerant pressure should be displayed. If pressure is displayed, recover refrigerant from equipment lines and then check refrigerant purity.
12. Confirm refrigerant purity in supply tank using ACR4 and refrigerant identifier.
13. Confirm refrigerant purity in vehicle A/C system using ACR4 and refrigerant identifier.
14. Discharge A/C system using approved refrigerant recovery equipment. Repair the leaking fitting or component as necessary.
15. Evacuate and recharge A/C system and perform the leak test to confirm no refrigerant leaks.
16. Conduct A/C performance test to ensure system works properly.

COMPRESSOR

Compressor Service Data & Specifications (SDS)

Lubricant Service Data & Specifications (SDS)

REFRIGERANT

Refrigerant Service Data & Specifications (SDS)

ENGINE IDLING SPEED

Refer to SERVICE & ADJUSTMENT SPECIFICATIONS .

BELT TENSION

Refer to BELT ADJUSTMENT .