A/c-Heater System - Automatic Audi A6 C4

A/C SYSTEM SPECIFICATIONS

AUTOMATIC A/C-HEATER SYSTEMS SPECIFICATIONS

DESCRIPTION

The A/C-heater control panel has buttons to control system. Blower speed is controlled automatically according to difference between selected temperature and interior temperature. Blower speed can also be controlled manually.

The A/C-heater control panel left side display shows selected temperature and automatic functions. (Scheme 1) The right side display indicates manual functions. The A/C-heater system micro-processor, located within A/C-heater control panel, has a self-diagnostic feature.

The A/C-heater system automatically maintains temperatures from 64°F (18°C) to 85°F (29°C). If temperature greater than 85°F (29°C) is selected, the word HI appears in temperature display. If temperature less than 64°F (18°C) is selected, the word LO is displayed. Selection of these temperatures overrides automatic climate control system.

Scheme 1

Zexel Compressors

Sensor is located on compressor and determines A/C compressor speed. A/C-heater control panel then compares compressor speed to engine speed and calculates belt slippage (as a percentage). If slippage is excessive, control panel switches compressor off.

A/C-Heater Control Panel

A/C-heater control panel has a digital microprocessor that compares values from various sensors. Microprocessor then activates appropriate flap motor and A/C compressor clutch to maintain desired temperature. A/C clutch, blower speed, temperature/blend air door position, and mode doors are all controlled by A/C-heater control panel.

Air Distribution

Three buttons control air distribution. (Scheme 1) When selected, uppermost air distribution button directs air to windows. When middle air distribution button is selected, air is directed to dashboard outlets and rear of center console. When lowermost air distribution button is selected, air is directed to footwells.

Automatic Mode

In this setting, air temperature, air delivery and air distribution are regulated automatically to achieve and maintain desired interior temperature. All previously selected settings are canceled.

Blower Speed Settings

Blower speed buttons can be used to raise or lower blower speed in all operating modes. Blower speed plus (+) button is used to raise blower speed. Minus (-) button lowers blower speed. If minus (-) button is pushed after blower speed is set at its lowest setting, climate control system will be deactivated.

Climate control system will also be deactivated if minus (-) and plus (+) buttons are pushed simultaneously. To reactivate system, press AUTO button, defrost button, one of temperature control buttons or blower speed plus (+) button.

Compressor On/Off Button

This button controls A/C compressor operation.

Defrost Mode

In this setting, recirculation door is open. Blower runs at highest speed and temperature is automatically regulated. All air is directed toward windshield.

Central Air Distribution Flap Motor

This actuator (motor) is located on front of heater box. The central air distribution flap is used to distribute airflow to instrument panel vents or to footwell/defroster outlets. A potentiometer, inside motor, indicates position of air distribution flap to A/C-heater control panel as a feedback value.

Footwell/Defroster Flap Motor

This actuator (motor) is located on front of heater box. The footwell/defroster flap distributes air to footwell or defroster outlets depending on mode selected. A potentiometer, inside motor, indicates position of air distribution flap to A/C-heater control panel as a feedback value.

Fresh Air/Recirculating Flap Motor (Vacuum Servo)

This vacuum-operated actuator is located on left side of evaporator assembly, in air plenum. A two-way vacuum valve is used to control the amount of vacuum applied to fresh air/recirculating flap motor. See TWO-WAY VACUUM VALVES .

Temperature Regulator Flap Motor

This actuator (motor) is mounted on left side of heater box. (Scheme 2) A potentiometer, inside motor, indicates position of air distribution flap to A/C-heater control panel as a feedback value.

The temperature regulator flap is used to control air temperature in vehicle passenger compartment. Air temperature regulation is accomplished by using two flaps, one flap before and one flap after heater core. The temperature-regulating flap actuating mechanism also operates turbulence flap.

Scheme 2

AMBIENT TEMPERATURE SENSORS

Two sensors measure outside air temperature and send input signals to A/C-heater control panel. A/C-heater control panel measures sensor readings and lowest temperature value to calculate correction factor for interior temperature regulation. One sensor is located in front of vehicle, behind lower air grille. Second sensor is located in evaporator, next to fresh air flap.

FRESH AIR TEMPERATURE SENSOR

Temperature sensor is located on heater box, downstream of fresh air fan. Sensor measures temperature of air leaving evaporator to provide quicker response time to changes of interior temperature.

FAN CONTROL UNIT

Air to passenger compartment is supplied and regulated by fan control unit. Fan control unit is mounted to evaporator box, in air plenum, and is cooled by airflow through evaporator housing. (Scheme 3)

Scheme 3

HIGH PRESSURE SWITCH

Switch controls cooling fan high speed operation. Switch is located on high pressure switch refrigerant line. Switch is identified by its Green housing. Ensure switch closes at 206-252 psi (14.48-17.72 kg/cm 2 ) . Ensure switch opens at 170-218 psi (12-15 kg/cm 2 ) . Difference between opening and closing points must be at least 29.0 psi (2.04 kg/cm 2 ) . Switch can be removed without discharging system.

HIGH PRESSURE CUT-OUT SWITCH

Switch is identified by Red housing and located on right/left side of condenser. Cut-out switch turns off A/C compressor clutch when refrigerant pressure reaches 409.0-450.0 psi (28.76-31.60 kg/cm 2 ) . Switch can be replaced without discharging system. Ensure switch closes at 149.0-250.0 psi (10.45-17.58 kg/cm 2 ) . Replace switch if necessary.

IN-CAR TEMPERATURE SENSORS

In-car temperature sensors measure interior air temperature and send signals to A/C-heater control panel. A small fan drives air over instrument panel sensor to ensure accurate measurement. One sensor is mounted on top of instrument panel, and a second sensor is located next to front dome light.

LOW PRESSURE SWITCH

Refrigerant low pressure switch disengages A/C compressor clutch if refrigerant pressure drops below specified pressure. Ensure switch opens at 21.0-23.0 psi (1.48-1.62 kg/cm 2 ) . Ensure switch closes at 42.0-49.0 psi (2.95-3.45 kg/cm 2 ) . Replace switch if necessary.

Fresh/Recirculated Air Flap

This two-way vacuum valve is used to control vacuum applied to fresh/recirculated air flap door vacuum servo. Valve is located on left side of evaporator assembly, in air plenum.

Two-way vacuum valve is controlled by signals from A/C-heater control panel. When vacuum is applied to fresh/recirculated air flap door vacuum servo, flap door closes and no fresh air enters vehicle.

Heater Control (Coolant) Valve

This vacuum valve is located on right side of heater box, in air plenum. (Scheme 2) Two-way vacuum valve is electrically controlled by signals from A/C-heater control panel, which directs or vents vacuum to heater control valve. When vacuum is applied to heater control valve, no coolant flows through heater core.

SELF-DIAGNOSTICS

Note. Scan Tester (VAG 1551) must be used to make full use of the system's self-diagnostic capabilities.

The complete self-diagnostics functions and operating instructions of VAG 1551 scan tester are not covered. Follow VAG 1551 operator's manual and accompanying trouble shooting manual. The following text highlights functions available when using VAG 1551 scan tester.

DIAGNOSTIC TROUBLE CODE MEMORY

Note. Diagnostic trouble code memory is cleared when ignition is turned off. DO NOT turn ignition off after driving vehicle, as this will erase fault codes.

If a malfunction occurs in a monitored sensor or component, a Diagnostic Trouble Code (DTC) is stored in memory. This function may be used by technician to access and erase DTCs. Codes may be either hard or intermittent failures.

Hard Failures

If A/C-heater system malfunctions are present for more than 5 seconds, they are stored as Diagnostic Trouble Codes (DTCs). The A/C compressor control module distinguishes data between 19 different trouble codes and stores malfunctions until ignition is turned off (volatile memory).

Intermittent Failures

If malfunction occurs intermittently, they are stored and considered to be "sporadic" (intermittent) failures. When displayed on scan tester, intermittent malfunctions will have "SP" (sporadic) on right side of display.

MEASURING VALUE BLOCK

Ten measuring value blocks, with 4 measuring channels each, are used. Monitored sensors and components include A/C compressor switch-off conditions, temperature regulator flap motor, central flap motor, footwell/defroster flap motor, airflow flap motor, and motor potentiometers.

Measuring value block function monitoring includes display and measuring values of all ambient, fresh air intake duct, and in-car temperature sensors. Voltage at fresh air blower, engine speed, A/C compressor speed, and vehicle speed are monitored. Inputs from Engine Coolant Temperature (ECT) sensor, kick-down switch, A/C compressor engagement, and A/C high pressure switch are also monitored.

OUTPUT DIAGNOSTIC TEST MODE

Since VAG 1551 scan tester is a bi-directional tester, it may be used to actuate a number of A/C-heater system components. The output diagnostic test mode may be used to actuate A/C compressor clutch, fresh air blower, temperature sensor blower fan, and cooling fan.

The A/C-heater control panel segment displays, outside temperature indicator (display), and Idle Air Control (IAC) may also be actuated.

In addition, temperature regulator flap motor, central flap motor, footwell/defroster flap motor, airflow flap motor, and fresh/recirculated air flap two-way valve may also be actuated.

A/C CONTROL HEAD CODING

Replacement A/C control heads (A/C-heater control panel) are sold with Code 000 and must be properly coded after installation. Contact nearest Audi parts department to determine correct application.

ON-BOARD DIAGNOSTICS (OBD)

Note. While OBD information is being displayed on A/C-heater control panel, A/C system operation does not take place (A/C compressor, radiator fan, etc. are not controlled).

ACCESSING MEMORY DIAGNOSTIC CHANNELS

1. Turn ignition switch on or start engine. Simultaneously press and hold down air recirculation button and air distribution (up arrow) button. (Scheme 1) Release both buttons. Display panel should read "01c", indicating diagnostic channel No. 1.
2. Pressing temperature plus (+) button will advance display of diagnostic channel by one. Display panel should read "02c", indicating diagnostic channel No. 2. Each time plus (+) button is pressed, system will advance to next diagnostic channel until last number is reached; display will then return to channel No. 1.
3. Memory diagnostic channels identify individual circuits, and are not fault codes. See «MEMORY DIAGNOSTIC CHANNELS»(/audi/a6/c4-1994-1997/remont/automatic-hvac-system/#ac-heater-system-automatic) table. To retrieve information about a particular channel, select desired channel then press air recirculation button.
4. If channel No. 52 is selected and A/C compressor switch-off condition exists, a segment of "88.8" display will illuminate indicating cause of condition. (Scheme 4)
5. Channel No. 53 is used to identify which A/C electrical components (outputs) are activated. When channel No. 53 is selected, a segment of "88.8" display will illuminate. (Scheme 4)
6. On both channels No. 52 and 53, segments 7, 14 and 21 of "88.8" display must illuminate simultaneously to indicate system function is okay. (Scheme 4)

EXITING ON-BOARD DIAGNOSTICS

To exit memory diagnostic channel display, press AUTO button or turn ignition off.

MEMORY DIAGNOSTIC CHANNELS

Scheme 4

RETRIEVING & CLEARING FAULT CODES

1. To retrieve fault codes using A/C-heater control panel, access memory diagnostic channels. See «ON-BOARD DIAGNOSTICS (OBD)»(/audi/a6/c4-1994-1997/remont/automatic-hvac-system/#ac-heater-system-automatic__on-board-diagnostics-obd) . If a diagnostic fault code exists, fault code will be displayed in channel No. 1. If no fault code exists, "00.0" will be displayed.
2. If a fault code exists, repair malfunction indicated. See «DIAGNOSTIC TROUBLE CODES»(/audi/a6/c4-1994-1997/remont/automatic-hvac-system/#ac-heater-system-automatic) table. After malfunction is corrected, clear diagnostic trouble codes. To clear codes, VAG 1551 must be used.

DIAGNOSTIC TROUBLE CODES

TESTING

A/C SYSTEM PERFORMANCE

1. Park vehicle out of direct sunlight. Ensure condenser and radiator are free of obstructions. Ensure compressor drive belt is in good condition. Ensure engine is at normal operating temperature. Close engine hood.
2. Start engine and run it at 2000 RPM. Turn A/C system on and press AUTO mode button. (Scheme 1) Press minus (-) button until "LO" temperature setting is displayed.
3. Press air recirculation button until recirculated air symbol is displayed. Press compressor on/off button until ice crystal symbol is displayed. (Scheme 1)
4. Open all instrument panel air outlets. Ensure cooling fan and A/C compressor run. Ensure blower motor runs on high speed and air flows out of instrument panel vents.
5. Using VAG 1551 scan tester, check DTC memory. Close doors, windows, and sun roof. Record ambient temperature and check outlet air temperature at center instrument panel vent after A/C system has run for 5 minutes. See «A/C SYSTEM PERFORMANCE SPECIFICATIONS»(/audi/a6/c4-1994-1997/remont/automatic-hvac-system/#ac-heater-system-automatic) table. NOTE: If A/C compressor clutch disengages during performance test, go to step 11). A/C SYSTEM PERFORMANCE SPECIFICATIONS Ambient Temp. °F (°C) Outlet Air Temp. °F (°C) 59 (15) 37-43 (3-6) 68 (20) 37-43 (3-6) 77 (25) 37-43 (3-6) 86 (30) 37-43 (3-6) 95 (35) 39-45 (4-7) 104 (40) 41-48 (5-8)
6. If outlet air temperature is not as specified, remove low pressure switch and jumper connector terminals. Remove high pressure switch, leaving its wiring harness connected. Connect manifold gauge set to high and low pressure service valves.
7. Repeat A/C system performance test. High side (discharge) pressure should increase from base pressure (engine off) to a maximum of 290 psi (20.4 kg/cm 2 ). See «A/C SYSTEM BASE (HIGH SIDE) PRESSURE SPECIFICATIONS»(/audi/a6/c4-1994-1997/remont/automatic-hvac-system/#ac-heater-system-automatic) table.
8. The high pressure switch should switch cooling fan to second speed between 190-254 psi (13.4-17.9 kg/cm 2 ). If cooling fan does not switch to second speed, check cooling fan circuit.
9. The low side (suction) pressure should be as specified in «A/C SYSTEM LOW SIDE PRESSURE SPECIFICATIONS»(/audi/a6/c4-1994-1997/remont/automatic-hvac-system/#ac-heater-system-automatic) table. If both high and low side pressures are okay, A/C system cooling performance is okay. Check low pressure and high pressure switches as necessary.
10. If either high or low side pressures are incorrect, check refrigerant and A/C system for malfunctions (low refrigerant charge, faulty compressor, kinked/plugged A/C hose, etc.). A/C SYSTEM BASE (HIGH SIDE) PRESSURE SPECIFICATIONS Ambient Temp. °F (°C) (1) psi (kg/cm 2 ) 59 (15) 56.6 (3.9) 68 (20) 68.2 (4.7) 77 (25) 81.2 (5.6) 86 (30) 97.2 (6.7) 95 (35) 113.1 (7.8) 104 (40) 132.0 (9.1) 113 (45) 152.3 (10.5) (1) Pressures listed are with engine off. A/C SYSTEM LOW SIDE PRESSURE SPECIFICATIONS Ambient Temp. °F (°C) Pressure psi (kg/cm 2 ) 50 (10) 30-32 (2.1-2.2) 59 (15) 29-32 (2.0-2.2) 68 (20) 28-30 (1.9-2.1) 77 (25) 26-29 (1.8-2.0) 86 (30) 25-29 (1.7-2.0) 95 (35) 25-30 (1.7-2.1) 104 (40) 28-33 (1.9-2.3)
11. Check Diagnostic Trouble Code (DTC) memory. See «DIAGNOSTIC TROUBLE CODE MEMORY»(/audi/a6/c4-1994-1997/remont/automatic-hvac-system/#ac-heater-system-automatic__diagnostic-trouble-code-memory) under SELF-DIAGNOSTICS. Repair A/C system malfunctions (if any). Erase DTC memory. End session using RAPID DATA TRANSFER, leaving VAG 1551 connected. Repeat A/C system performance test.
12. Ensure scan tester is in A/C/HEATING ELECTRONICS function. With RAPID DATA TRANSFER displayed on scan tester, press "0" and "8" buttons to select READ MEASURING VALUE BLOCK function. Press "Q" button to enter input.
13. With INPUT DISPLAY GROUP NUMBER displayed on scan tester, press "0" and "1" buttons to select COMPRESSOR SWITCH-OFF CONDITIONS. Press "Q" button to enter input.
14. Read display group No. 1, channel No. 1. If Code 2 (high pressure cut-out switch) is displayed, go to next step. If Code 3 (low pressure switch) is displayed, go to step 20). If other codes are displayed, go to «MEASURING VALUE BLOCK»(/audi/a6/c4-1994-1997/remont/automatic-hvac-system/#ac-heater-system-automatic__measuring-value-block) under SELF-DIAGNOSTICS.
15. End session using RAPID DATA TRANSFER. Remove high pressure cut-out switch, leaving its wiring harness connected. Connect manifold gauge set to high pressure cut-out switch Schrader valve.
16. Repeat A/C system performance test and check A/C system high side pressure. High side (discharge) pressure should increase from base pressure (engine off) to a maximum of 290 psi (20.4 kg/cm 2 ). See «A/C SYSTEM BASE (HIGH SIDE) PRESSURE SPECIFICATIONS»(/audi/a6/c4-1994-1997/remont/automatic-hvac-system/#ac-heater-system-automatic) table.
17. The high pressure switch should switch cooling fan to second speed between 190-254 psi (13.4-17.9 kg/cm 2 ). If cooling fan does not switch to second speed, check cooling fan circuit.
18. If required cooling performance is attained and no other malfunction is detected, replace high pressure cut-out switch. If high side pressure is exceeded, check refrigerant and A/C system for malfunctions.
19. If A/C compressor clutch still does not engage, check wiring harness between A/C control panel and high pressure cut-out switch. Repair wiring harness as necessary.
20. End session using RAPID DATA TRANSFER. Remove low pressure switch and jumper connector terminals. Connect manifold gauge set to low pressure switch Schrader valve.
21. Repeat A/C system performance test and check A/C system low side pressure. Low side (suction) pressure should be as specified in «A/C SYSTEM LOW SIDE PRESSURE SPECIFICATIONS»(/audi/a6/c4-1994-1997/remont/automatic-hvac-system/#ac-heater-system-automatic) table.
22. If required cooling performance is attained and no other malfunction is detected, replace low pressure switch. If low side pressure is incorrect, check refrigerant and A/C system for malfunctions (low refrigerant charge, faulty A/C compressor, kinked/plugged A/C hose, etc.).
23. If A/C compressor clutch disengages during test, check wiring harness between A/C control panel and low pressure switch. Repair wiring harness as necessary.
24. If A/C compressor clutch does not disengage during test, check heater box and evaporator assembly for air leaks. If no leaks are found, A/C system may be low on refrigerant. Check refrigerant lines and components for leaks. Repair leaks as necessary.

ACTUATORS, SENSORS & FAN CONTROL MODULE

Note. Manufacturer recommends the use of VAG 1551 scan tester for circuit and component testing.

AUTOMATIC A/C-HEATER SYSTEM COMPONENT TESTING

AMBIENT, IN-CAR & FRESH AIR TEMPERATURE SENSOR RESISTANCE VALUES

REMOVAL & INSTALLATION

1. Discharge A/C system, using approved refrigerant recovery/recycling equipment. Mark direction of drive belt. Loosen drive belt tensioner and remove drive belt. Remove bracket for refrigerant line. Remove bolts and A/C compressor. Remove and plug high and low pressure lines from A/C compressor.
2. To install, reverse removal procedure. Tighten connections to specification. See «TORQUE SPECIFICATIONS»(/audi/a6/c4-1994-1997/remont/automatic-hvac-system/#ac-heater-system-automatic) table. Evacuate and charge A/C system.

Removal & Installation (Zexel Compressors)

Discharge A/C system, using approved refrigerant recovery/recycling equipment. Disconnect speed sensor connector. Remove screws and sensor. To install, reverse removal procedure. Tighten screws to specification. See TORQUE SPECIFICATIONS table.

Note. Before removing A/C-heater control panel, check for codes. See SELF-DIAGNOSTICS .

Turn ignition off. Carefully pry off A/C-heater control panel trim. Remove screws and A/C-heater control panel. To install, reverse the removal procedure. Tighten screws to proper specification. See TORQUE SPECIFICATIONS table.

1. To remove fresh air/recirculating flap vacuum motor, remove plenum tray. Rotate vacuum motor 90 degrees, and pull from mount. Disconnect vacuum hose, and secure aside. DO NOT allow vacuum hose to slide into evaporator housing. Remove fresh air/recirculating flap motor (vacuum servo).
2. To remove temperature regulator flap motor, remove plenum tray. Entirely remove windshield wiper motor and linkage assembly. Remove cover and temperature regulator flap motor.
3. To remove central flap and footwell/defroster flap motor, remove center console. See «CENTER CONSOLE»(/audi/a6/c4-1994-1997/remont/automatic-hvac-system/#ac-heater-system-automatic). Remove glove box and driver's side tray. Remove defroster hoses from left and right sides of heater box.
4. Remove central flap and footwell/defroster flap motor support tray screws from left and right sides of heater box. Disconnect wiring harness Blue connector at central flap motor. (Scheme 5)
5. Disconnect wiring harness Red connector at footwell/defroster flap motor. Remove central flap and footwell/defroster flap motor support tray. Remove motor(s) from support tray. To install, reverse removal procedure.

Scheme 5

Removal & Installation (Rear)

1. Obtain radio anti-theft protection code. Disconnect negative battery cable. Unscrew and remove gearshift knob. Disengage gearshift lever trim from retaining clip. Remove gearshift lever trim.
2. Unclip cigarette trim plate, and remove self-tapping screws. Lift up lining, and remove self-tapping screw. Pull out rear air duct and disconnect electrical connectors. Remove rear air duct.
3. Slide driver's and passenger's seats fully forward. Pull parking brake lever up as far as possible. Carefully pry handle from parking brake lever. Remove screws and clip securing front of console. Remove bolts securing rear center console. Remove rear center console. To install, reverse removal procedure.

Note. Front center console can be removed without removing center section of instrument panel.

Removal & Installation (Front)

Remove rear center console. Unclip cover and remove nut. Remove radio. Pull out center air outlet, and remove bolts. Remove trim plates. Remove bolts and ashtray. Loosen bolts at front of console. Remove front center console. To install, reverse removal procedure.

1. Discharge A/C system, using approved refrigerant recovery/recycling equipment. Remove glove box. Remove 4 evaporator cover bolts. Remove plenum tray. Disconnect and plug refrigerant lines. Disconnect evaporator housing electrical connections. Remove evaporator housing.
2. To install, reverse removal procedure. Use NEW seal between evaporator and firewall. Use NEW "O" rings. Tighten connections to specification. See «TORQUE SPECIFICATIONS»(/audi/a6/c4-1994-1997/remont/automatic-hvac-system/#ac-heater-system-automatic) table. Ensure water drain hose connections and tightly sealed, and hose is not kinked. Ensure water drain valve operates properly. Ensure no air leaks exist.

Remove plenum tray. Remove heater box. See HEATER BOX . Remove intake duct with fresh air flap. Remove locking clip, retaining washer and grommet. To install, reverse removal procedure. Lubricate mounting tabs with petroleum jelly.

Remove glove box. Disconnect wiring harness connector from fan control (fresh air blower) control module. Carefully remove fan control module (heat sink may be hot). To install, reverse removal procedure.

Remove right side plenum tray. Remove fresh air intake duct grille. Remove glove box. Twist temperature sensor, and remove from fresh air duct. To install sensor, spray sensor seal with silicone. Reverse removal procedure to complete installation.

HEATER BOX

Note. Heater box can be removed without discharging A/C system.

Removal

1. Remove plenum tray. Remove wiper motor/linkage assembly. Remove center console. See «CENTER CONSOLE»(/audi/a6/c4-1994-1997/remont/automatic-hvac-system/#ac-heater-system-automatic) . Remove glove box and driver's side tray. Remove footwell air outlet on driver's and passenger's side.
2. Remove rubber coupling between evaporator housing and heater box. Remove hoses and connecting bellows to rear heater duct. Remove connections between heater box and evaporator housing. Loosen cap on coolant expansion tank. Disconnect coolant hoses from heater box. Remove screw and tensioning strap.
3. Disconnect heater box electrical connections. Attach Engine Support Bridge (10-222 A/1) and Heater Claw (2075) to lip of heater box. Tighten nut on engine support bridge to loosen heater box. Remove engine support bridge and heater claw. Remove heater box.

Installation

To install, reverse removal procedure. Replace adhesive sealing tape, positioning sealing tape ends at top of heater box. Check rubber coupling for leaks. When assembling housing, apply silicon rubber to area of housing above temperature flap.

Remove plenum tray. Loosen coolant expansion tank cap to relieve pressure. Disconnect coolant hoses from heater core. Plug coolant hoses to prevent contamination. Remove coolant hoses from valve. Remove screw and heater control valve. To install, reverse removal procedure.

Remove glove box. Disconnect hose and wiring harness from sensor. Remove screws and in-car temperature sensor. To install, reverse removal procedure. Ensure hose is securely attached.

Remove rear and front center consoles. See CENTER CONSOLE . Remove center section of instrument panel. Remove steering wheel. Remove steering column switch. Remove bolts and trim strip. Remove screws and instrument cluster. To install, reverse removal procedure.

1. Discharge A/C system, using approved refrigerant recovery/recycling equipment. Loosen refrigerant line clamp and remove lines from evaporator. Using needle nose pliers, remove restrictor (orifice tube) from evaporator inlet. Plug openings to prevent contamination.
2. To install, reverse removal procedure. Use NEW "O" rings. Insert orifice tube with arrow pointing toward evaporator, and push until firmly seated.

TORQUE SPECIFICATIONS

TORQUE SPECIFICATIONS

A/C-Heater System Wiring Diagram (Early 95 Prod'n - 1 Of 2). Scheme 6

A/C-Heater System Wiring Diagram (Early 95 Prod'n - 2 Of 2). Scheme 7

A/C-Heater System Wiring Diagram (Late 95 Prod'n/96 1 Of 2). Scheme 8

A/C-Heater System Wiring Diagram (Late 95 Prod'/96 - 2 Of 2). Scheme 9

See also:
• TWO-WAY VACUUM VALVES
• ON-BOARD DIAGNOSTICS (OBD)
• DIAGNOSTIC TROUBLE CODE MEMORY
• MEASURING VALUE BLOCK
• OUTPUT DIAGNOSTIC TEST MODE
• SELF-DIAGNOSTICS
• HEATER BOX