A/c-Heater System - Manual Buick LeSabre VII

TORQUE SPECIFICATIONS

DESCRIPTION

The manual A/C-heater system delivers heated or cooled and dehumidified air. System is a Cycling Clutch Orifice Tube (CCOT) design, using a Harrison HD6/HR6-HE compressor. Air distribution is controlled through a soft-touch manual A/C-heater control panel and electric/vacuum-operated actuator doors.

OPERATION

OFF

No blower operation or air conditioning occurs in this mode. As vehicle moves, a slight amount of ram air enters passenger compartment.

RECIRC

Blower is turned on and speed can be adjusted using fan speed control. Compressor can be activated by selecting A/C button. Interior air is pulled into system by blower. If A/C is selected, air is cooled and dehumidified, then heated as necessary, and forced out of dash outlets.

BI-LEVEL

Conditioned air is directed through dash registers and floor outlets.

BLEND

Warm air flows from windshield and floor outlets.

DEFROST

In this mode, outside air is pulled into system by blower. Air is cooled and dehumidified, then heated as necessary and forced out the windshield defroster outlets.

DEFOG

Air is evenly split between floor outlets and windshield defroster outlets.

HTR (Heater)

Compressor does not operate in this mode. Outside air is heated and distributed, with approximately 80 percent to floor outlets and 20 percent to windshield and side windows.

MAX

Maximum cooling is provided in this mode. Conditioned air is distributed through dash registers. This is the only mode in which inside air is recirculated.

NORM

Conditioned air is directed through dash registers.

VENT

In this mode, the compressor does not operate. Outside air is delivered through dash registers.

A/C PRESSURE FAN SWITCH

The pressure fan switch is a normally closed switch that monitors high side pressure during A/C operation. When high side pressure reaches 210 psi (14.7 kg/cm 2 ), the switch opens, signaling the Powertrain Control Module (PCM). PCM then turns up primary cooling fan to high speed. When high side pressure drops to about 160 psi (11.2 kg/cm 2 ), the switch closes, signaling PCM to halt high speed fan operation.

COMPRESSOR CONTROL RELAY

The compressor control relay cycles the compressor clutch on and off. With ignition on, battery voltage is applied to compressor control relay common contact and one of the compressor clutch contacts. The second compressor clutch contact is grounded by the Powertrain Control Module (PCM). When A/C or defrost mode is selected, the pressure cycling switch is closed, and relay energizes compressor clutch.

HIGH PRESSURE CUT-OUT SWITCH

The high pressure cut-out switch inhibits compressor operation if high side pressure exceeds approximately 430 psi (30 kg/cm 2 ) to prevent compressor damage and refrigerant loss. After pressure drops to less than approximately 200 psi (14 kg/cm 2 ), compressor operation resumes.

HIGH PRESSURE RELIEF VALVE

The high pressure relief valve is mounted on rear of A/C compressor. Valve acts as safety device. Valve opens to prevent system damage when refrigerant pressure exceeds 530 psi (37 kg/cm 2 ), venting refrigerant to atmosphere.

ORIFICE TUBE

The orifice tube controls liquid refrigerant flow into evaporator. The orifice tube has filter screens on both inlet and outlet sides. The tube has no moving parts. Replace plugged or defective orifice tube.

PRESSURE CYCLING SWITCH

The pressure cycling switch, mounted on accumulator fitting, senses compressor suction pressure. If orifice tube becomes plugged or if a massive discharge occurs, the pressure cycling switch inhibits compressor clutch operation. The pressure cycling switch opens at 22 psi (1.5 kg/cm 2 ) and closes at 43 psi (3.0 kg/cm 2 ).

OPERATIONAL TESTING

When trouble shooting and diagnosing an air conditioning system, always refer to appropriate vacuum and wiring diagrams for the system involved.

If blower operates at all speeds and compressor clutch engages, electrical circuits are functioning properly. If evaporator inlet pipe and accumulator surface appear to be the same temperature when felt by hand, system is properly charged with refrigerant. Ensure vacuum and diaphragm function properly when moving selector control.

BLOWER INOPERATIVE

1. Turn ignition switch to RUN position. Set A/C-heater control in RECIRC position. Set blower speed to high. Using a test light, backprobe between high speed blower motor relay Purple wire terminal and ground. If test light does not illuminate, go step 3). If test light illuminates, go to next step.
2. Check for open in Purple wire to blower motor or open in Black wire to blower motor. Check for poor blower motor connections. If circuits and connections are okay, replace blower motor.
3. Backprobe high speed blower motor relay connector Orange wire terminal and ground. If test light does not illuminate, go to next step. If test light illuminates, check for poor connection at high speed blower motor relay connector. If connection is okay, replace high speed blower motor relay.
4. Backprobe blower speed relay Light Blue wire terminal to A/C-heater control. If test light does not illuminate, go to next step. If test light illuminates, check for open in Light Blue wire. Check for poor connection at A/C-heater connector. If circuit and connection are okay, replace A/C-heater control.
5. Remove blower speed relay. Using a test light connected to battery voltage, backprobe blower speed relay connector Brown wire terminal to A/C-heater control. If test light does not illuminate, go to next step. If test light illuminates, check for open in Brown wire to fuse block. If circuit is okay, replace blower speed relay.
6. Check for open in Brown wire from blower speed relay to A/C-heater control. Check for poor connection at A/C-heater control connector. If circuit and connection are okay, replace A/C-heater control assembly.

HIGH SPEED INOPERATIVE, LOW & MEDIUM SPEEDS OPERATE NORMALLY

1. Turn ignition switch to RUN position. Set A/C-heater control to RECIRC position. Set blower speed to high. Using a test light, backprobe high speed blower relay Orange wire terminal and ground. If test light illuminates, go to next step. If test light does not illuminate, go to step 3).
2. Backprobe high speed blower relay Dark Blue wire terminal and ground. If test light illuminates, check for open or poor connection at high speed blower relay Black wire connector to ground splice. If circuit or connector is okay, replace high speed blower relay. If test light does not illuminate, repair open in Red wire terminal from high speed blower relay to underhood fuse block.
3. Backprobe between A/C-heater control Orange wire terminal and ground. If test light illuminates, check for open or shorted circuit or poor connection between A/C-heater control and high speed blower relay. If test light does not illuminate, check for poor connection at A/C-heater control assembly. If connection is okay, replace A/C-heater control assembly.

LOW SPEED INOPERATIVE, MEDIUM & HIGH SPEEDS OPERATE NORMALLY

1. Turn ignition to RUN position. Set A/C-heater control to RECIRC position. Set blower speed to low. Using a test light, backprobe blower motor resistor Light Blue wire terminal and ground. If test light does not illuminate, go to next step. If test light illuminates, check for poor connection at blower resistor connector. If connector is okay, replace blower motor resistor.
2. Check for open or short in Light Blue wire between blower motor resistor and splice. If circuit is okay, replace A/C-heater control assembly.

MEDIUM SPEED(S) INOPERATIVE, LOW & HIGH SPEEDS OPERATE NORMALLY

1. Turn ignition switch to RUN position. Set A/C-heater to RECIRC position. Set blower speed to M1 position. Using a test light, backprobe blower motor resistor Tan wire terminal and ground. If test light illuminates, go to step 3). If test light does not illuminate, go to next step.
2. Check for open or poor connection at Tan wire connector between blower motor resistor and A/C-heater control. Check for poor connection at A/C-heater control connector to blower motor resistor. If circuit and connection are okay, replace A/C-heater control assembly.
3. Set blower switch to M2 position. Using a test light, backprobe blower motor resistor connector Light Blue wire terminal and ground. If test light does not illuminate, go to next step. If test illuminates, check for poor connection at blower motor resistor connector. If connection is okay, replace blower motor resistor.
4. Check for open circuit or poor connection at Light Blue wire connector between blower motor resistor and A/C-heater control. If circuit and connection are okay, replace A/C-heater control assembly.

INSUFFICIENT COOLING/HEATING

1. Remove center instrument panel insert. Turn ignition switch to RUN position. Observe A/C temperature valve actuator arm (located at center of dash, near plenum) as temperature selector is moved from full cold to full hot position. If temperature valve actuator arm makes a complete travel, go to next step. If temperature valve actuator arm does not make a full travel, go to step 3).
2. Turn ignition off. Adjust temperature valve link rod (located in A/C-heater module, in engine compartment). To adjust, remove (snap out) temperature valve link rod from temperature valve. Start engine. Set blower fan to high and temperature to full hot. Allow 45 seconds for A/C temperature actuator to move to full hot position. Move temperature valve to full hot position and snap link rod into temperature valve.
3. Turn ignition off. Remove (snap out) temperature link rod from temperature valve. Manually move temperature valve to left and right. If temperature valve is sticking or binding, replace temperature valve assembly. If temperature valve can be moved smoothly, go to next step.
4. Disconnect A/C-heater control connectors. Turn ignition switch to RUN position. Measure voltage between A/C-heater control assembly connector terminal A8 (Brown wire) and passenger compartment fuse block. If battery voltage is present, go to next step. If reading is less than battery voltage, turn ignition off. Check for open or short in Brown wire from A/C-heater control connector and fuse block. Check fuse No. 5A in passenger compartment fuse block.
5. Check voltage in A/C-heater control terminal A8 (Brown wire). If battery voltage is present, go to next step. If reading is less than battery voltage, turn ignition off. Check for open in Black wire between A/C-heater control and ground splice.
6. Turn ignition off. Check A/C-heater control connectors for proper terminal contact. If contacts are okay, reconnect A/C-heater control connectors. Disconnect temperature valve actuator connector.
7. Turn ignition switch to RUN position. Check voltage between temperature control valve actuator connector Brown wire terminal and ground. If battery voltage is present, go to next step. If reading is less than battery voltage, turn ignition off. Check for open in Brown wire.
8. Check voltage between temperature valve actuator connector Brown wire and Yellow wire terminals. If battery voltage is present, go to next step. If reading is less than battery voltage, turn ignition off. Check connector or for open or short in Yellow wire between temperature valve actuator and A/C-heater control. If circuit or connector is okay, replace A/C-heater control assembly.
9. Check voltage between temperature valve actuator connector Dark Blue wire and Yellow wire terminals while moving temperature selector from full cold to full warm position. If voltage varies from less than 1 volt (full cold) to battery voltage (full hot), go to next step. If voltage does not vary, turn ignition off. Check connector or for open in Dark Blue wire. If connector or circuit is okay, replace A/C-heater control assembly.
10. Turn ignition off. Check temperature valve actuator connector for proper terminal contact. If contact is okay, replace temperature valve actuator.

AIR FLOWS FROM WRONG OUTLETS (ELECTRONIC A/C)

1. Road test vehicle and ensure cruise control system (if equipped) is operating properly. If cruise control is operating properly, go to next step. If cruise control is not operating properly, check for leaking or restricted vacuum source from engine or vacuum check valve. Check for leaking vacuum hose to cruise control servo or vacuum tank. Check for proper vacuum hose routing.
2. With engine idling, check for vacuum at Violet vacuum hose at A/C solenoid switch assembly. If vacuum is present, go to next step. If vacuum is not present, check and repair leak or restriction in Violet hose.
3. Disconnect vacuum connector from A/C-heater programmer. With engine idling, use a 3-inch piece of vacuum hose connected to vacuum source. Jump to each air door actuator vacuum line. See AIR DOOR ACTUATOR HOSE IDENTIFICATION table. If all of air door actuators fully open, go to next step. If any of air door actuators does not fully open, check for leaking or restricted vacuum line to actuator. Check for defective air door actuator or binding linkages. AIR DOOR ACTUATOR HOSE IDENTIFICATION Actuator Hose Color Bottom Air Door Red Center Air Door Light Green Defogger Outlet Door Blue Right Side Inlet Door Orange
4. Turn engine off. Turn ignition switch to RUN position. Disconnect A/C solenoid switch assembly harness connector terminal No. 5 (Brown wire). Using a test light, check for battery voltage at A/C solenoid switch terminal No. 5 (Brown wire). If test light illuminates, go to next step. If test light does not illuminate, check for open or short in Brown wire from A/C solenoid switch to fuse block.
5. Connect test light to battery voltage. Backprobe A/C solenoid switch terminal No. 6 (Black wire). If test light illuminates, got to next step. If test light does not illuminate, check for open in Black wire to ground.
6. Using test light, check if test light illuminates when connected between specified A/C solenoid switch terminal and ground with mode buttons depressed in each specified position. See A/C SOLENOID SWITCH RESPONSE table under A/C SOLENOID SWITCH TEST.
7. If test light illuminates as indicated, check A/C solenoid switch assembly harness connector for proper contact. If contacts are okay, replace A/C solenoid switch assembly. If test light did not illuminate on any or all of A/C solenoid switch connector terminals, check for an open or short in circuit. If circuit is okay, replace A/C-heater control assembly.

A/C DOES NOT WORK

With engine running and function control switch at NORM position, check for voltage at pressure cycling switch. Check for voltage between pressure cycling switch and compressor clutch. Ground compressor clutch circuit. If clutch engages, check wide-open throttle cut-out switch and A/C compressor cut-off switch.

Insufficient Cooling

Note. QUICK CHECK procedure may be used to check for proper refrigerant charge in A/C system, provided ambient air temperature is more than 70°F (21°C). On vehicles with Cycling Clutch Orifice Tube (CCOT) system, compressor will cycle on and off to meet system requirements. CCOT system does not use a sight glass to check refrigerant charge.

Quick Check Procedure

1. Engine must be at normal operating temperature (not on fast idle or cold enrichment). Open vehicle doors and engine hood. Select NORM A/C position. Move temperature lever to COLD position. Turn blower switch to HI position. Engine should be at normal slow idle speed.
2. While compressor is engaged, feel temperature of accumulator surface and evaporator inlet pipe. If temperature of both components is the same (slightly cooler than ambient air), system is normal. If inlet pipe is frosted or feels cooler than accumulator surface, refrigerant charge is low.
3. Add refrigerant in 4-ounce increments, allowing system to stabilize between additions, until accumulator and pipe appear to be same temperature. Add 14 more ounces of refrigerant.

Thorough Check Procedure

See CCOT System trouble shooting flow charts below.

Scheme 1

Scheme 2

Scheme 3

Scheme 4

TESTING

A/C SYSTEM PERFORMANCE

1. Park vehicle out of direct sunlight. Install manifold gauge set. Start engine. Turn A/C on. Place A/C control to maximum cooling, selector lever on full cold and blower switch on HIGH. Close vehicle doors and windows.
2. Insert thermometer in center air outlet. Run engine at idle for 5 minutes. Measure temperature and system pressures. Temperatures and pressures should be within correct range. See A/C SYSTEM PERFORMANCE TEMPERATURE SPECIFICATIONS and A/C SYSTEM PERFORMANCE PRESSURE SPECIFICATIONS tables.

A/C SYSTEM PERFORMANCE TEMPERATURE SPECIFICATIONS

A/C SYSTEM PERFORMANCE PRESSURE SPECIFICATIONS

A/C SOLENOID SWITCH TEST

1. Turn ignition off. Disconnect A/C solenoid switch connector, located behind glove box. Turn ignition switch to RUN position. Using a test light, check for voltage at solenoid switch connector terminal No. 5 (Brown wire) and ground. If test light illuminates, go to next step. If test light does not illuminate, check for open or short in Brown wire.
2. Using test light, check if test light illuminates when connected between specified A/C solenoid switch terminal and ground with mode buttons depressed in each specified position. See A/C SOLENOID SWITCH RESPONSE table. A/C SOLENOID SWITCH RESPONSE Terminal & Selector Position (1) Test Light No. 1 (Dark Green) OFF, HTR, BLEND & FRONT On No. 2 (Light Green) OFF, VENT, HTR, BLEND, FRONT, NORM & BI-LEV On No. 3 (Pink) OFF, HTR, BLEND & BI-LEV On No. 4 (Purple) VENT, BLEND, FRONT, MAX, NORM & BI-LEV On OFF & HTR 1 Volt (1) Test light connected to ground and specified A/C solenoid switch connector terminal.
3. If test light illuminates as indicated, check A/C solenoid switch assembly harness connector for proper contact. If contacts are okay, replace A/C solenoid switch assembly. If test light did not illuminate on any or all of A/C solenoid switch connector terminals, check for an open or short in circuit. If circuit is okay, replace A/C-heater control assembly.

A/C TEMPERATURE VALVE ACTUATOR TEST

1. Disconnect A/C temperature valve actuator connector located behind glove box. Turn ignition switch to RUN position. Measure voltage between actuator connector terminal No. 10 (Brown wire) and ground. If battery voltage is present, go to next step. If battery voltage is not present, check Brown wire for open or short to ground.
2. Measure voltage between actuator connector terminals No. 7 (Yellow wire) and No. 8 (Dark Blue wire) while moving temperature selector from cool to warm position. If voltage varies from less than 1 volt (full cool) to battery voltage (full warm), go to step 4). If voltage varies, go to next step.
3. Check for open in Dark Blue wire. Check that in-line connector and A/C-heater control panel connector terminal are properly connected. If wiring and connections are okay, replace A/C-heater control panel.
4. Turn ignition off. Check A/C-heater control panel connector terminal for proper connection. If connection is okay, replace A/C-heater temperature valve actuator.

REMOVAL & INSTALLATION

Disconnect negative battery cable. Discharge A/C system using approved refrigerant recovery/recycling equipment. Remove rear engine sight shield (cover panel). Unplug A/C pressure cycling switch connector. Remove accumulator clamp screw. Disconnect accumulator inlet and outlet refrigerant line fittings. Remove accumulator from vehicle. To install, reverse removal procedure. If new accumulator is installed, add 3.5 ounces of clean refrigerant oil. Evacuate, recharge and leak test A/C system.

Disconnect negative battery cable. Remove center trim plate retaining screws and trim plate. Remove control panel retaining screws. Pull control panel out enough to remove electrical and vacuum connections. Remove control panel. To install, reverse removal procedure.

1. Disconnect negative battery cable. Remove instrument panel. Drain cooling system. Remove nuts and strut tower cross brace. Remove spark plug wires and bracket from back side of engine. Remove evaporator. Disconnect heater hoses from heater core. Remove power steering pump.
2. Disconnect vacuum hose and remove air distributor. Remove bolt attaching A/C-heater assembly to front of dashboard. Remove bolts and studs attaching assembly to rear of dash, repositioning insulator as necessary. Rotate assembly to clear rear corner of engine and remove A/C-heater module. To install, reverse removal procedure. Evacuate, recharge and leak test system.

Disconnect negative battery cable. Remove glove box. Remove vacuum connector from switch assembly. Disconnect electrical connector. Remove solenoid switch attaching screws and remove solenoid. To install, reverse removal procedure.

Disconnect negative battery cable. Remove nuts and cross brace. Unplug blower motor electrical connector from blower motor. Remove cooling tube. Remove blower motor screws. Remove blower motor and fan as an assembly. To install, reverse removal procedure.

1. Disconnect negative battery cable. Remove rear engine shield (cover panel). Remove center bolt and positive battery cable from relay and fuse bracket. Remove underhood fuse/relay block from bracket. Remove bracket.
2. Remove electrical connectors from blower control module and blower motor resistor. Remove retaining screws and blower motor resistor. To install, reverse removal procedure.

1. Disconnect negative battery cable. Discharge A/C system using approved refrigerant recovery/recycling equipment. Remove compressor drive belt. Remove front upper compressor mounting bolt. Raise and support vehicle. From underneath vehicle, remove A/C compressor splash shield. Unplug electrical connectors from compressor.
2. Remove bolt retaining refrigerant lines to compressor. Remove remaining compressor mounting bolts and compressor. To install, reverse removal procedure. If more than one ounce of oil was drained from compressor, add same amount of clean refrigerant oil to new compressor. If less than one ounce was drained, add two ounces of clean refrigerant oil to new compressor. Evacuate, recharge and leak test A/C system.

1. Remove battery. Discharge A/C system using approved refrigerant recovery/recycling equipment. Remove air cleaner bracket screw. Remove and plug transmission cooler lines (if equipped). Remove upper radiator panel. Disconnect condenser inlet and outlet lines.
2. Remove condenser mounting brackets and upper insulators. Tilt condenser toward radiator and pull upward to remove. To install, reverse removal procedure. Add one ounce clean refrigerant oil to new condenser. Tighten inlet and outlet lines to 18 ft. lbs. (24 N.m). Evacuate, recharge and leak test A/C system.

1. Disconnect negative battery cable. Discharge A/C system using approved refrigerant recovery/recycling equipment. Remove accumulator. See ACCUMULATOR under REMOVAL & INSTALLATION. Remove blower control case and blower motor. See BLOWER MOTOR under REMOVAL & INSTALLATION. Remove vacuum reservoir.
2. Remove evaporator tube. Remove brackets and heat shield from blower case. Remove screws retaining driver's side of blower case to firewall. Cut insulation along indicated line. Remove insulator. Remove A/C-heater module. Remove evaporator. To install, reverse removal procedure. Add 3 ounces clean refrigerant oil to new evaporator. Evacuate, recharge and leak test A/C system.

HEATER CORE

Tools Required

J 37097 Mubea Hose Clamp Pliers

Removal

1. Drain engine cooling system.
2. Remove heater hoses from heater core fittings. (Scheme 5)
3. Remove air mix valve actuator (C61 & C67), or programmer (C68 & CJ2).
4. Remove heater core cover retaining screws and cover. (Scheme 6)
5. Remove retaining screws and heater core.

Heater Hoses At Heater Core. Scheme 5

Heater Core Cover. Scheme 6

Installation

1. Install heater core into vehicle and attaching screws.
2. Install heater core cover and tighten screws to 12 INCH Lbs (1.4 N.m). (Scheme 6)
3. Install air mix valve actuator (C61 & C67), or programmer (C68 & CJ2) and tighten screws to 12 INCH Lbs (1.4 N.m)
4. Install heater hoses to heater core fittings using J37097. (Scheme 5)
5. Fill and pressure test cooling system.

High pressure cut-out switch is located at rear of compressor. Disconnect negative battery cable. Discharge A/C system using approved refrigerant recovery/recycling equipment. Raise and support vehicle. Unplug switch electrical connector. Using snap ring pliers, remove switch retainer. Withdraw switch from rear head of compressor. Remove and discard "O" ring.

Coat NEW "O" ring with refrigerant oil. Install "O" ring into switch cavity groove. Coat new switch with refrigerant oil, and install into switch cavity. Install switch retainer and electrical connector. Lower vehicle. Evacuate, recharge and leak test A/C system.

Note. Different orifice tube types are used. When replacing an orifice tube, compare its design and color to replacement part. Different types of orifice tubes are not interchangeable.

1. Orifice tube is located in line between condenser and evaporator. Discharge A/C system using approved refrigerant recovery/recycling equipment. Disconnect condenser outlet fitting. Disconnect evaporator inlet fitting. Remove A/C refrigerant line clamp.
2. Using Orifice Tube Remover (J-26549-D), remove orifice tube. To install, assemble evaporator inlet and condenser outlet dual "O" ring joints simultaneously (hand tight) to assure correct line orientation. Tighten dual "O" ring joint to 25 ft. lbs. (34 N.m). Evacuate, recharge and leak test A/C system.

Disconnect negative battery cable. Unplug pressure cycling switch electrical connector. Pressure cycling switch is mounted on a Schrader-type valve at accumulator; discharging refrigerant system is not necessary. Unscrew switch. Remove "O" ring. To install, coat new "O" ring with refrigerant oil. Install pressure cycling switch. Reconnect electrical wiring.

TORQUE SPECIFICATIONS

Scheme 7

Manual A/C-Heater System Wiring Diagram. Scheme 8