A/c-Heater System - Automatic: Diagnosis Mazda Millenia I

TROUBLE SHOOTING

PRELIMINARY INSPECTION

Operate A/C-heater system to verify customer's concerns. Carefully check for damaged/loose connections, misrouted wiring circuits, and/or blown fuses. Repair or replace as necessary. If problem(s) remain after repairs have been made, go to SYMPTOM DIAGNOSIS and/or SELF-DIAGNOSTICS.

Note. Perform SYSTEM OPERATION CHECK after repairs are made.

SYMPTOM DIAGNOSIS

Note. If unable to enter self-diagnostics, go to TEST NO. 1 (A/C AMPLIFIER POWER SOURCE).

Note. Start and operate engine until coolant temperature is at least 104-212°F (40-100°C).

Cannot Enter Self-Diagnostics

Go to TEST NO. 1 (A/C AMPLIFIER POWER SOURCE).

SELF-DIAGNOSTICS

Note. If self-diagnostics cannot be entered, go to TEST NO. 1 (A/C AMPLIFIER POWER SOURCE).

Self-diagnostic feature of A/C amplifier detects all electrical faults (past and present) in the control circuit and stores them as trouble codes for diagnosis. System self-diagnostics can also individually check for correct operation of output devices. Following features are available in self-diagnostics: present diagnostic mode, past diagnostic mode and output inspection mode.

ENTERING SELF-DIAGNOSTICS

1. Start and warm engine to operating temperature. Turn ignition off. Connect NGS Tester (49 T088 0A0) to Data Link Connector (DLC) and battery. Place NGS tester in AUX 1 setting. Select VEHICLE & ENGINE SELECTION on NGS tester display menu. Select correct information on display menu (vehicle model, engine type and model year).
2. Select DIAGNOSTIC DATA LINK on display menu. Select A/C-AIR CONDITIONER MODULE on display menu. Select DIAGNOSTIC TEST MODE on display menu. Follow instructions on NGS tester to enter system self-diagnostics.

Note. If no light strikes solar temperature sensor, self-diagnostic system will falsely indicate a fault in solar temperature sensor circuit (Code 02).

OUTPUT INSPECTION MODE

To enter output inspection mode, press AUTO switch while in present diagnostic mode. This mode individually checks operation of each output device and its circuit. Output inspection consists of 4 individual steps. (Scheme 1) Start output inspection mode with step No. 1, and then proceed to next step in numerical order. To advance to next step, press air intake selector switch. After reaching step No. 4, pressing air intake selector switch again will return to step No. 1 of output inspection mode.

Scheme 1

TEST NO. 1 (A/C AMPLIFIER POWER SOURCE)

1. Turn ignition on. Measure voltage at Blue/White wire terminal of A/C amplifier 26-pin female connector. If voltage is zero volts, go to next step. If voltage is not zero volts, repair Blue/White wire between A/C amplifier and ground.
2. Measure voltage at Pink/Green wire terminal of A/C amplifier 26-pin female connector. If battery voltage is present, go to next step. If battery voltage is not present, repair open and/or short in Pink/Green wire between A/C amplifier and RADIO fuse (10-amp) in joint box.
3. Measure voltage at Green wire terminal of A/C amplifier 22-pin female connector. If battery voltage is present, replace A/C amplifier. If battery voltage is not present, repair Green wire between A/C amplifier and A/C fuse (10-amp) in joint box.

TEST NO. 2 (BLOWER MOTOR)

1. Turn ignition on. Set blower switch to fourth speed position. Measure voltage at Blue/Red wire terminal of blower motor female connector. If battery voltage is present, go to next step. If battery voltage is not present, go to step 4).
2. Measure voltage at Black/White wire terminal of blower motor female connector. If voltage is zero volts, replace blower motor. If voltage is not zero volts, go to next step.
3. Measure voltage at Black wire terminal of MAX-HI (maximum-high) relay female connector. If voltage is zero volts, repair Black/White wire between blower motor and MAX-HI relay. If voltage is not zero volts, repair Black wire between MAX-HI relay and ground.
4. Measure voltage at Black/Yellow wire terminal of blower relay female connector. If voltage is zero volts, go to next step. If voltage is not zero volts, go to step 8).
5. Measure voltage at Red/White wire terminal of blower relay female connector. If battery voltage is present, go to next step. If battery voltage is not present, repair open and/or short in Red/White wire between BLOWER fuse (15-amp) in joint box and blower relay.
6. Measure voltage at Blue wire terminal of blower relay female connector. If battery voltage is present, go to next step. If battery voltage is not present, repair Blue wire between HEATER fuse (40-amp) in main fuse block and blower relay.
7. Measure voltage at Blue/Red wire terminal of blower relay female connector. If battery voltage is present, repair wiring between blower relay and blower motor (Blue/Red wire changes to Blue wire then back to Blue/Red wire). If battery voltage is not present, replace blower relay.
8. Measure voltage at Black/Yellow wire terminal of A/C amplifier 26-pin connector. If voltage is zero volts, repair Black/Yellow wire between blower relay and A/C amplifier. If voltage is not zero volts, replace A/C amplifier.

TEST NO. 3 (POWER TRANSISTOR)

1. Test power transistor. See «POWER TRANSISTOR»(ref-37734-S14975841732001010900000) under TESTING. If power transistor is okay, go to next step. Replace power transistor if it does not test as indicated.
2. Disconnect blower motor connector. Check continuity of Black/White wire between power transistor female connector and blower motor female connector. If continuity exists, go to next step. If continuity does not exist, repair Black/White wire between power transistor and blower motor.
3. Check continuity of Black wire between power transistor female connector and ground. If continuity exists, go to next step. If continuity does not exist, repair Black wire between power transistor and ground.
4. Disconnect A/C amplifier 26-pin connector. Check continuity of Blue/Red wire between power transistor female connector and A/C amplifier 26-pin female connector. If continuity exists, go to next step. If continuity does not exist, repair Blue/Red wire between power transistor and A/C amplifier.
5. Check continuity of Black/White wire between power transistor female connector and A/C amplifier 26-pin female connector. If continuity exists, replace A/C amplifier. If continuity does not exist, repair Black/White wire between power transistor and A/C amplifier.

TEST NO. 4 (MAX-HI RELAY)

1. Disconnect power transistor connector. Turn ignition on. Set blower switch in fourth speed position. Measure voltage at Green wire terminal of MAX-HI (maximum-high) relay female connector. If battery voltage is present, go to next step. If battery voltage is not present, repair open and/or short in Green wire between A/C fuse (10-amp) in joint box and MAX-HI relay.
2. Measure voltage at Orange wire terminal of MAX-HI relay female connector. If voltage is zero volts, go to next step. If voltage is not zero volts, go to step 5).
3. Measure voltage at Black/White wire terminal of MAX-HI relay female connector. If voltage is zero volts, repair Black/White wire between blower motor and MAX-HI relay. If voltage is not zero volts, go to next step.
4. Measure voltage at Black wire terminal of MAX-HI relay female connector. If voltage is zero volts, replace MAX-HI relay. If voltage is not zero volts, repair Black wire between MAX-HI relay and ground.
5. Measure voltage at Blue wire terminal of A/C amplifier 22-pin female connector. If voltage is zero volts, repair wiring between MAX-HI relay and A/C amplifier (Blue wire becomes Orange wire at MAX-HI relay). If voltage is not zero volts, replace A/C amplifier.

TEST NO. 5 (AIR INTAKE ACTUATOR)

1. Remove air intake actuator. Turn ignition on. Place blower switch in fourth speed position. Manually operate air intake crank. If air intake mode changes smoothly from recirculated air to fresh air, go to next step. If air intake mode does not change smoothly, inspect blower unit.
2. Test air intake actuator. See ACTUATORS under TESTING. If actuator is okay, go to next step. Replace air intake actuator if it does not test as specified.
3. Turn ignition switch to LOCK position. Disconnect A/C amplifier 26-pin connector. Check continuity between terminals of air intake actuator female connector and A/C amplifier 26-pin female connector. See «WIRING DIAGRAM»(ref-37734-S36524318502001010900000) for wire colors. If continuity exists, replace A/C amplifier. If continuity does not exist, repair appropriate wire(s).

TEST NO. 6 (AIRFLOW MODE ACTUATOR)

Note. If Code 21 (present) or Code 22 (past) exists, begin testing at step 2).

1. Remove airflow mode actuator. Turn ignition on. Set blower switch at fourth speed setting. Manually operate airflow mode main link. If airflow mode changes smoothly through each mode, go to next step. If airflow mode does not change smoothly, inspect heater unit.
2. Test airflow mode actuator. See ACTUATORS under TESTING. If actuator is okay, go to next step. Replace airflow mode actuator if it does not test as specified.
3. Turn ignition switch to LOCK position. Disconnect A/C amplifier 26-pin connector. Check continuity between terminals of airflow mode actuator male connector and A/C amplifier 26-pin female connector. See «WIRING DIAGRAM»(ref-37734-S36524318502001010900000) for wire colors. If continuity is as specified, go to next step. If continuity is not as specified, repair appropriate wire(s).
4. Disconnect A/C amplifier 22-pin connector. Check continuity between airflow mode actuator male connector and A/C amplifier 22-pin female connector. See «WIRING DIAGRAM»(ref-37734-S36524318502001010900000) for wire colors. If continuity is as specified, replace A/C amplifier. If continuity is not as specified, repair appropriate wire(s).

TEST NO. 7 (ELECTRICAL LOAD IDLE-UP)

1. Turn ignition on. Measure voltage at Violet/White wire terminal of A/C amplifier 26-pin female connector. If battery voltage is present, go to next step. If battery voltage is not present, check continuity of Violet/White wire between A/C amplifier and Engine Control Module (ECM). If wire is okay, check ECM. See appropriate TESTS W/CODES article in ENGINE PERFORMANCE.
2. Set blower switch at fourth speed setting. Measure voltage at Violet/White wire of A/C amplifier 26-pin connector. If voltage is zero volts, check ECM. See appropriate TESTS W/CODES article in ENGINE PERFORMANCE. If voltage is not zero volts, replace A/C amplifier.

TEST NO. 8 (AIR MIX ACTUATOR)

1. Start and warm engine to operating temperature. Turn ignition switch to LOCK position. Disconnect A/C amplifier connectors (22-pin and 26-pin). Disconnect blower motor connector. Apply battery voltage to Blue/Red wire terminal of blower motor male connector, and ground Black/White wire terminal.
2. Apply battery voltage to Green/Yellow wire terminal of A/C amplifier 26-pin female connector, and ground Green/Black wire terminal. Ensure airflow temperature changes. Connect ohmmeter between Green/Orange wire and Purple wire terminals of A/C amplifier 22-pin female connector.
3. While observing ohmmeter, reverse battery polarity between Green/Yellow wire and Green/Black wire terminals at A/C amplifier 26-pin female connector. Ensure resistance reading changes progressively from 800 ohms to 5200 ohms as air mix door moves from maximum cold position to maximum hot position. Ensure outlet air temperature changes from cold to hot.
4. If outlet air temperature and resistance are as specified, replace A/C amplifier. If outlet air temperature and resistance are not as specified, check if Code 18 (present) or Code 19 (past) is set. If either code is set, remove all jumper wires and go to step 6). If neither code is set, remove all jumper wires and go to next step.
5. Remove air mix actuator. Start and warm engine to operating temperature. Set blower switch in fourth speed position. Manually operate air mix crank. If discharge air temperature changes smoothly, go to next step. If temperature does not change smoothly, inspect heater unit.
6. Turn ignition switch to LOCK position. Disconnect A/C amplifier 26-pin connector. Check continuity between air mix actuator female connector and A/C amplifier 26-pin female connector. See «WIRING»(ref-37734-S36524318502001010900000) DIAGRAM for wire color. If continuity exists in all wires, go to next step. If continuity does not exist in all wires, repair appropriate wire(s).
7. Disconnect A/C amplifier 22-pin connector. Check continuity between air mix actuator female connector and A/C amplifier 22-pin female connector. See «WIRING DIAGRAM»(ref-37734-S36524318502001010900000) for wire colors. If continuity exists in all wires, replace air mix actuator. If continuity does not exist, repair appropriate wire(s).

TEST NO. 9 (TAIL NUMBER SIDE - TNS LIGHTS)

1. If information display does not illuminate properly, go to next step. If AMB switch LED indicator does not illuminate properly, go to step 3). If LED indicators on A/C-heater control unit DO NOT illuminate properly, replace A/C amplifier. For all other symptoms, go to step 5).
2. Disconnect A/C amplifier 26-pin connector. Disconnect connector from information display. Check continuity of Green/White wire between A/C amplifier 26-pin female connector and information display female connector. If continuity exists, replace A/C amplifier and/or information display. If continuity does not exist, repair Green/White wire between A/C amplifier and information display.
3. Turn ignition on. Turn on light switch. Measure voltage at Red wire terminal of A/C amplifier 22-pin female connector. If battery voltage is present, go to next step. If battery voltage is not present, check continuity of Red wire between TNS relay and A/C amplifier. If Red wire is okay, inspect TNS relay.
4. Turn ignition switch to LOCK position. Turn off light switch. Disconnect A/C amplifier 20-pin connector, located between A/C-heater control unit and A/C amplifier. Check continuity between terminals 3J and 3L of A/C amplifier 20-pin female connector. (Scheme 2)and (Scheme 4). If continuity exists, reconnect 20-pin connector and go to next step. If continuity does not exist, replace A/C-heater control unit.
5. Connect jumper wire between ground and White/Violet wire terminal of A/C amplifier 26-pin female connector. Turn ignition on. Turn on light switch. If A/C-heater control unit lights illuminate, check continuity of White/Violet wire between A/C amplifier and interior lights system. If A/C-heater control unit lights DO NOT illuminate, replaceA/C amplifier.

Scheme 2

TEST NO. 10 (INDICATOR LIGHTS)

1. Turn ignition on. Press AUTO switch, windshield and rear window defrost switches, and air intake selector switch. If any LED indicator does not come on, go to next step. If all LED indicators DO NOT come on, go to step 3).
2. Measure voltage at A/C amplifier 20-pin female connector terminal(s) of inoperative LED indicator(s). See «A/C-HEATER CONTROL»(ref-37734-S16626973492001010900000) UNIT-TO-A/C AMPLIFIER CONNECTOR CIRCUIT IDENTIFICATION table. If voltage is zero volts, replace A/C-heater control unit. If voltage is not zero volts, replace A/C amplifier.
3. Measure voltage at terminal 3N of A/C amplifier 20-pin female connector. (Scheme 2)and (Scheme 4). If battery voltage is present, go to next step. If battery voltage is not present, replace A/C amplifier.
4. Measure voltage at terminal 3M of A/C amplifier 20-pin female connector. If voltage is zero volts, replace A/C-heater control unit. If voltage is not zero volts, replace A/C amplifier.

A/C-HEATER CONTROL UNIT-TO-A/C AMPLIFIER CONNECTOR CIRCUIT IDENTIFICATION

TEST NO. 11 (SERIAL COMMUNICATION)

Note. If information display does not illuminate, begin testing at step 3).

1. Disconnect A/C amplifier 26-pin connector and information display connector. Check continuity of Green/White and Yellow/Black wires between A/C amplifier 26-pin female connector and information display female connector. If continuity exists in both wires, go to next step. If continuity does not exist in both wires, repair appropriate wire(s).
2. Disconnect A/C amplifier 22-pin connector. Check continuity of White and Yellow/Red wires between A/C amplifier 22-pin female connector and information display female connector. If continuity exists in both wires, go to next step. If continuity does not exist in both wires, repair appropriate wire(s).
3. Ensure ignition is off. Check continuity between ground and Green wire terminal of A/C amplifier 22-pin female connector (backprobe). If continuity exists, go to next step. If continuity does not exist, replace A/C amplifier.
4. Disconnect A/C amplifier 22-pin connector and information display connector. Check continuity of Green wire terminal between A/C amplifier 22-pin female connector and information display female connector. If continuity exists, inspect information display. If continuity does not exist, repair open in Green wire.

TEST NO. 12 (AMBIENT TEMPERATURE INDICATION)

1. Turn ignition on. Measure voltage at White/Black wire terminal of A/C amplifier 22-pin female connector. If voltage is 3.6 volts, go to next step. If voltage is not 3.6 volts, replace A/C amplifier.
2. Press and hold AMB switch in on position. Measure voltage at White/Black wire terminal of A/C amplifier 22-pin female connector. If voltage is not zero volts, go to next step. If voltage is zero volts, replace A/C amplifier.
3. Turn AMB switch off. Measure voltage at White/Black wire terminal of information display female connector. If voltage is 3.6 volts, replace information display. If voltage is not 3.6 volts, repair White/Black wire between A/C amplifier and information display.

TEST NO. 13 (A/C AMPLIFIER BACK-UP POWER SOURCE)

Measure voltage at Blue/Red wire terminal of A/C amplifier 26-pin female connector. If battery voltage is present, replace A/C amplifier. If battery voltage is not present, repair Blue/Red wire between ROOM fuse (15-amp) in joint box and A/C amplifier.

TEST NO. 14 (AMBIENT TEMPERATURE SENSOR)

1. Test ambient temperature sensor. See «SENSORS»(ref-37734-S25395375872001010900000) under TESTING. If sensor is okay, go to next step. Replace sensor if it does not test as specified.
2. Disconnect A/C amplifier 22-pin connector. Check continuity of Red/Green and Green/Orange wires between A/C amplifier 22-pin female connector and ambient temperature sensor male connector. If continuity exists in both wires, replace A/C amplifier. If continuity does not exist in both wires, repair open in appropriate wire(s).

TEST NO. 15 (SOLAR TEMPERATURE SENSOR)

1. Test solar temperature sensor. See «SENSORS»(ref-37734-S25395375872001010900000) under TESTING. If sensor is okay, go to next step. Replace sensor if it does not test as specified.
2. Disconnect A/C amplifier 22-pin connector. Check continuity of Red/Yellow wire between A/C amplifier 22-pin female connector and solar temperature sensor female connector. If continuity exists, go to next step. If continuity does not exist, repair open in Red/Yellow wire.
3. Disconnect A/C amplifier 26-pin connector. Check continuity of White wire between A/C amplifier 26-pin female connector and solar temperature sensor female connector. If continuity exists, replaceA/C amplifier. If continuity does not exist, repair open in White wire.

TEST NO. 16 (PASSENGER COMPARTMENT TEMPERATURE SENSOR)

1. Test Passenger Compartment Temperature (PCT) sensor. See «SENSORS»(ref-37734-S25395375872001010900000) under TESTING. If sensor is okay, go to next step. Replace sensor if it does not test as specified.
2. Disconnect A/C amplifier 22-pin connector. Check continuity of White/Violet and Green/Orange wires between A/C amplifier 22-pin female connector and PCT sensor female connector. If continuity exists in both wires, replace A/C amplifier. If continuity does not exist in both wires, repair open in appropriate wire(s).

TEST NO. 17 (WATER TEMPERATURE SENSOR)

1. Test water temperature sensor. See «SENSORS»(ref-37734-S25395375872001010900000) under TESTING. If sensor is okay, go to next step. Replace sensor if it does not test as specified.
2. Disconnect A/C amplifier 22-pin connector. Check continuity between Red/Black wire terminal of A/C amplifier 22-pin female connector and water temperature sensor female connector. If continuity exists, go to next step. If continuity does not exist, repair open in Red/Black wire between A/C amplifier and water temperature sensor.
3. Check continuity of Green/Orange wire between A/C amplifier 22-pin female connector and water temperature sensor female connector. If continuity exists, replace A/C amplifier. If continuity does not exist, repair open in Green/Orange wire.

TEST NO. 18 (EVAPORATOR TEMPERATURE SENSOR)

1. Test evaporator temperature sensor. See «SENSORS»(ref-37734-S25395375872001010900000) under TESTING. If sensor is okay, go to next step. Replace sensor if it does not test as specified.
2. Disconnect A/C amplifier 22-pin connector. Check continuity of Red/White and Green/Orange wires between A/C amplifier 22-pin female connector and evaporator temperature sensor female connector. If continuity exists in both wires, replace A/C amplifier. If continuity does not exist in both wires, repair open in appropriate wire(s).

TEST NO. 19 (A/C SIGNAL)

1. Test refrigerant pressure switch. See REFRIGERANT PRESSURE SWITCH under TESTING. If pressure switch is okay, go to next step. Replace pressure switch if it does not test as specified.
2. Disconnect refrigerant pressure switch connector. Turn ignition on. Measure voltage at Green wire terminal of pressure switch female connector. If voltage is not 5 volts, go to next step. If voltage is 5 volts, reconnect pressure switch connector and go to step 4).
3. Check continuity of Green wire between pressure switch and Engine Control Module (ECM). If necessary, repair Green wire. If wire is okay, inspect ECM. See appropriate TESTS W/CODES article in ENGINE PERFORMANCE.
4. Measure voltage at Green/Black wire terminal of A/C amplifier 22-pin female connector. If voltage is 5 volts, go to next step. If voltage is not 5 volts, repair Green/Black wire between pressure switch and A/C amplifier.
5. Set blower switch in fourth speed position. Turn A/C switch on. Measure voltage at Green/Black wire terminal of A/C amplifier 22-pin female connector. If voltage is outside of specified range, replaceA/C amplifier. If voltage is 3.1-3.5 volts or less than 1.5 volts, inspect ECM. See appropriate TESTS W/CODES article in ENGINE PERFORMANCE.

TEST NO. 20 (A/C POWER SOURCE)

1. Measure voltage at Red/Blue wire terminal of condenser fan relay No. 1 female connector. If battery voltage is present, go to next step. If battery voltage is not present, repair Red/Blue wire between AD FAN fuse (30-amp) and condenser fan relay No. 1.
2. Measure voltage at Blue/White wire terminal of condenser fan relay No. 1 female connector. If battery voltage is not present, repair Blue/White wire between ENGINE fuse (15-amp) in joint box and condenser fan relay No. 1. If battery voltage is present, inspect Engine Control Module (ECM). See appropriate TESTS W/CODES article in ENGINE PERFORMANCE.

TEST NO. 21 (COMPRESSOR CLUTCH)

1. Connect jumper wire between ground and Light Green/Yellow wire of A/C relay female connector. Turn ignition on. If compressor clutch does not engage, go to next step. If compressor clutch engages, check continuity of Light Green/Yellow wire between A/C relay and Engine Control Module (ECM). If necessary, repair Light Green/Yellow wire. If wire is okay, inspect ECM. See appropriate TESTS W/CODES article in ENGINE PERFORMANCE.
2. Measure voltage at Blue/Red wire terminal of A/C relay female connector. If battery voltage is not present, go to next step. If battery voltage is present, go to step 5).
3. Measure voltage at Red/Blue wire terminal of A/C relay female connector. If battery voltage exists, go to next step. If battery voltage does not exist, repair Red/Blue wire between AD FAN fuse (30-amp) in main fuse block and A/C relay.
4. Measure voltage at Blue/White wire terminal of A/C relay female connector. If battery voltage exists, replace A/C relay. If battery voltage does not exist, repair Blue/White wire between ENGINE fuse (15-amp) in joint box and A/C relay.
5. Measure voltage at Blue/Red wire terminal of compressor clutch female connector. If battery voltage exists, replace compressor clutch. If battery voltage does not exist, repair Blue/Red wire between A/C relay and compressor clutch.

TEST NO. 22 (CONDENSER FAN)

1. Connect jumper wire between ground and Red/White wire terminal of condenser fan relay No. 1 female connector. Turn ignition on. If condenser fan does not operate, go to next step. If condenser fan operates, check continuity of Red/White wire between condenser fan relay No. 1 and Engine Control Module (ECM). If necessary, repair Red/White wire. If wire is okay, inspect ECM. See appropriate TESTS W/CODES article in ENGINE PERFORMANCE.
2. Measure voltage at Blue/Green wire terminal of condenser fan relay No. 1 female connector. If battery voltage exists, go to step 5). If battery voltage does not exist, go to next step.
3. Measure voltage at Red/Blue wire terminal of condenser fan relay No. 1 female connector. If battery voltage exists, go to next step. If battery voltage does not exist, repair Red/Blue wire between AD FAN fuse (30-amp) in main fuse block and condenser fan relay No. 1.
4. Measure voltage at Black/White wire terminal of condenser fan relay No. 1 female connector. If battery voltage exists, replace condenser fan relay No. 1. If battery voltage does not exist, repair Black/White wire between ENGINE fuse (15-amp) in joint box and condenser fan relay No. 1.
5. Measure voltage at Blue/Green wire terminal of condenser fan female connector. If battery voltage exists, go to next step. If battery voltage does not exist, repair Blue/Green wire between condenser fan and condenser fan relay No. 1.
6. Measure voltage at Green wire terminal of condenser fan female connector. If voltage is zero volts, test condenser fan. See «CONDENSER FAN»(ref-37734-S37644851792001010900000) under TESTING. If voltage is not zero volts, repair Green wire between condenser fan and condenser fan relay No. 1.

TEST NO. 23 (COOLING FAN)

Check continuity of Green wire between condenser fan, condenser fan relay No. 2 and coolant fan relay No. 2. Repair as necessary. If wires are okay, inspect coolant fan system.

TEST NO. 24 (CONDENSER FAN RELAY NO. 2)

1. Connect jumper wire between ground and Red/White wire terminal of condenser fan relay No. 1 female connector. Connect second jumper wire between ground and Yellow wire terminal of condenser fan relay No. 2 female connector. Turn ignition on.
2. If condenser fan does not operate, go to next step. If condenser fan operates, check continuity of Yellow wire between condenser fan relay No. 2 and Engine Control Module (ECM). If necessary, repair Yellow wire. If wire is okay, inspect ECM. See appropriate TESTS W/CODES article in ENGINE PERFORMANCE.
3. Measure voltage at Black/White wire terminal of condenser fan relay No. 2 female connector. If battery voltage exists, go to next step. If battery voltage does not exist, repair Black/White wire between ENGINE fuse (15-amp) in joint box and condenser fan relay No. 2.
4. Measure voltage at Black wire terminal of condenser fan relay No. 2 female connector. If voltage is zero volts, go to next step. If voltage is not zero volts, repair Black wire between condenser fan relay No. 2 and ground.
5. Measure voltage at Green wire terminal of condenser fan relay No. 2 female connector. If voltage is zero volts, repair Green wire between condenser fan and condenser fan relay No. 2. If voltage is not zero volts, replace condenser fan relay No. 2.

TEST NO. 25 (VEHICLE SPEED CONTROLS)

1. Raise front of vehicle. Place gear selector lever in Neutral. Manually rotate both front wheels at the same time. Measure voltage at Green/Red wire terminal of A/C amplifier 26-pin female connector. If voltmeter needle does not fluctuate between zero and 5 volts, go to next step. If voltmeter needle fluctuates between zero and 5 volts, replace A/C amplifier.
2. Disconnect A/C amplifier 26-pin connector. Disconnect speedometer 16-pin connector. Check continuity of Green/Red wire between A/C amplifier 26-pin female connector and speedometer 16-pin female connector. If continuity exists, inspect speedometer. If continuity does not exist, repair Green/Red wire.

TEST NO. 26 (A/C-HEATER CONTROL UNIT)

Note. If discharge air temperature does not correspond to temperature control setting, begin testing at step 2).

1. Test A/C-heater control unit. See «A/C-HEATER CONTROL UNIT»(ref-37734-S13907249012001010900000) under TESTING. Replace A/C-heater control unit if it does not test as specified. If A/C-heater control unit tests okay, replace A/C amplifier.
2. Turn ignition on. Measure voltage at terminal 3R of A/C amplifier 20-pin female connector, located between A/C amplifier and A/C-heater control unit. (Scheme 2)and (Scheme 4). If voltage is 5 volts, go to next step. If voltage is not 5 volts, replace A/C amplifier.
3. Measure voltage at terminal 3S of A/C amplifier 20-pin female connector. If battery voltage exists, go to next step. If battery voltage does not exist, replace A/C amplifier.
4. Turn ignition switch to LOCK position. Check continuity between ground and terminal 3T of A/C amplifier 20-pin female connector. If continuity does not exists, replace A/C amplifier. If continuity exists, check continuity of wire between A/C amplifier and A/C-heater control unit. If wire is okay, replace A/C amplifier or A/C-heater control unit.

TEST NO. 27 (REFRIGERANT SYSTEM)

1. Test A/C system performance. See «A/C SYSTEM PERFORMANCE»(ref-37734-S04952295762001010900000) under TESTING. If system pressures are not as specified, diagnose and repair system accordingly. See «REFRIGERANT SYSTEM DIAGNOSIS DIRECTORY»(ref-37734-S32014408012001010900000) table. If high pressure and low pressure readings are the same, check for improper A/C compressor operation. See «TEST NO. 28 (VANE NOISE)»(ref-37734-S17647934652001010900000) . REFRIGERANT SYSTEM DIAGNOSIS DIRECTORY High Pressure Reading Low Pressure Reading Go To More Than Spec. More Than Spec. Step 2) Less Than Spec. Less Than Spec. Step 3) * (1) (2) Step 4) * (3) Negative Pressure Step 5) (1) Slightly less than specification. (2) Slightly more than specification. (3) Momentarily rises to specified range, then drops to less than specification.
2. Check for clogged or damaged condenser fins. Repair as necessary. Ensure there is sufficient refrigerant in system. If condenser fins are not clogged or damaged, check if there is too much refrigerant. Adjust as necessary.
3. Perform gas leak test. If leak or oil stains exist, repair as necessary. If leak and oil stains are not present, check for insufficient refrigerant caused by occasional leakage. Correct refrigerant level if necessary.
4. Check if heat-sensing tube is properly positioned and securely connected to evaporator outlet pipe. Re-install tube if necessary. If tube is properly positioned and secured, replace malfunction expansion valve.
5. Turn blower switch off and wait about 10 minutes. Place blower switch in fourth speed position. Check pressure readings immediately after compressor is shut off. If pressure readings are normal, expansion valve is clogged due to frozen moisture. Replace receiver-drier.
6. If pressure readings are not normal, check if heat-sensing tube is properly positioned. Re-install tube if necessary. If tube is properly positioned, replace expansion valve.

TEST NO. 28 (VANE NOISE)

Note. Brief vane noise immediately following compressor start-up is considered normal.

1. If vane noise occurs after replacing refrigerant system components, go to next step. If noise occurs during refrigerant charge or if charging system after replacing a component, go to step 5). If noise occurs at excessively low idle, adjust idle speed. If noise does not occur as described, go to step 3).
2. Ensure compressor oil is properly added after replacing a component. For evaporator unit replacement, add 1.7 ounces of compressor oil. For condenser replacement, add 0.7 ounce of compressor oil. For receiver-drier replacement, add 0.3 ounce of compressor oil. For refrigerant line replacement, add 0.3 ounce of compressor oil. If compressor oil has been properly added, go to step 5).
3. Check for correct refrigerant charge. If refrigerant charge is okay, go to next step. If refrigerant charge is incorrect, adjust as necessary.
4. Turn ignition switch to LOCK position. Check for oil stains. If oil stains DO NOT exist, go to next step. If oil stains exist, repair as necessary.
5. Operate engine at constant speed of 3000-4000 RPM. Alternately turn compressor on and off (turn A/C switch on and off). If noise persists, turn ignition off for 1-2 minutes. Restart engine and operate it at constant speed of 3000-4000 RPM. Alternately turn compressor on and off. If noise remains, replace compressor.

TESTING

A/C AMPLIFIER PIN VOLTAGE TEST

Note. For connector pin/terminal identification (Scheme 4)thru (Scheme 6).

Remove A/C-heater control unit. See A/C-HEATER CONTROL UNIT under REMOVAL & INSTALLATION. Reconnect all A/C amplifier connectors. Measure voltage at indicated terminals of A/C amplifier female connector. Ensure voltage is as specified. See appropriate A/C AMPLIFIER PIN VOLTAGE TEST table. If voltage is not as specified, check appropriate circuit(s) and input/output device(s). Repair or replace as necessary. If circuit(s) and input/output device(s) are okay, replace A/C amplifier.

A/C AMPLIFIER PIN VOLTAGE TEST (26-PIN CONNECTOR)

A/C AMPLIFIER PIN VOLTAGE TEST (22-PIN CONNECTOR)

A/C AMPLIFIER PIN VOLTAGE TEST (20-PIN CONNECTOR) (1)

Scheme 3

Scheme 4

Scheme 5

Scheme 6