HVAC System - Automatic: Diagnosis Ford Taurus III

TROUBLE SHOOTING

PRELIMINARY INSPECTION

Operate automatic A/C-heater system to verify customer's concern. Carefully check the following for possible cause of problems and repair as necessary: damaged vacuum hose, incorrect refrigerant level, damaged drive belt, blown fuses, damaged/misrouted wiring circuits, and damaged/disconnected connectors. If problem remains after repairs have been made, go to SELF-DIAGNOSTIC TEST.

SELF-DIAGNOSTIC TEST

Note. Coolant temperature must be at least 120°F (49°C) before entering self-diagnostics.

Entering Self-Diagnostics

1. Simultaneously depress OFF and FLOOR buttons, then press AUTO button within 2 seconds. Display will show a pulse tracer going around the center of the display window for up to 30 seconds while test is running.
2. If DTCs are displayed, perform test indicated. See «SELF-DIAGNOSTIC TEST CODE DIRECTORY»(ref-39943-S01716573502001011200000) table. If no DTCs are displayed, go to «SYMPTOM DIAGNOSIS»(ref-39943-S10741196292001011200000) .
3. Self-diagnostics can be initiated at any time with the resulting DTCs being displayed. Normal system operation is stopped when system is in self-diagnostic mode.

Exiting Self-Diagnostics

To exit self-diagnostics, press Blue button on integrated control panel.

SELF-DIAGNOSTIC TEST CODE DIRECTORY

SELF-DIAGNOSTIC TEST CODE DIRECTORY

SYMPTOM DIAGNOSIS

Note. Diagnose a problem by its symptom only if no codes were recorded during SELF-DIAGNOSTIC TEST .

1. No Module Communication - Go to «TEST E»(ref-39943-S04682191852001011200000) .
2. EATC System Inoperative, Intermittent or Improper Operation - Go to «TEST F»(ref-39943-S30995219442001011200000) .
3. Blower Motor Inoperative - Go to «TEST G»(ref-39943-S18683299202001011200000) .
4. Blower Motor Operates At High Speed At All Speed Settings - Go to «TEST H»(ref-39943-S06272431472001011200000) .
5. Blower Motor Inoperative In High Setting - Go to «TEST J»(ref-39943-S40685058112001011200000) .
6. Blower Motor Inoperative In All Lower Speed Settings - Go to «TEST K»(ref-39943-S13730443462001011200000) .
7. A/C System Inoperative Or Does Not Operate Properly - Go to «TEST L»(ref-39943-S22515871062001011200000) .
8. Temperature Display Will Not Shift Between °F & °C - Go To «TEST M»(ref-39943-S33163778362001011200000) .

TEST A - BLEND DOOR ACTUATOR MOTOR INOPERATIVE OR OPERATES IMPROPERLY

1. Check Actuator Drive Access blend door actuator connector. Turn ignition on. Using a jumper wire, connect Dark Blue/Light Green wire to ground. Observe blend door operation. In the same manner, connect Orange wire to ground and observe blend door operation. If blend door does not operate in both directions, go to next step. If blend door operates in both directions, go to step 4).
2. Check Dark Blue/Light Green Wire Measure resistance between Dark Blue/Light Green wire at blend door actuator harness connector and ground. If resistance is greater than 12 ohms, go to next step. If resistance is less than 12 ohms, repair short to ground in Dark Blue/Light Green wire. Retest system.
3. Check Orange Wire Measure resistance between Orange wire at RCC module connector and ground. If resistance is greater than 12 ohms, system is operational. Test is complete. If resistance is less than 12 ohms, repair short to ground in Orange wire. Retest system.
4. Resistance Check Disconnect RCC module harness connector. Disconnect blend door actuator harness connector. Measure resistance of indicated circuits between specified RCC module connector and blend door actuator. See «EATC CIRCUIT RESISTANCE TEST»(ref-39943-S19660162222001011200000) table. If resistance in each circuit is 5 ohms or less, go to next step. If resistance in any circuit is greater than 5 ohms, repair wiring as necessary. EATC CIRCUIT RESISTANCE TEST RCC Module Connector Wire Color Blend Door Connector Wire Color Yellow/Light Green Yellow/Light Green Red/White Red/White Red/Light Green Red/Light Green Orange Orange Dark Blue/Light Green Dark Blue/Light Green
5. Resistance Check Drive blend door actuator to the fully clockwise (maximum heat) position. Disconnect connector from rear of RCC module. Check resistances between indicated wires. See «BLEND DOOR ACTUATOR RESISTANCE TEST»(ref-39943-S04347085092001011200000) table. If resistances are as specified, go to next step. If resistances are not as specified, replace blend door actuator and retest system. BLEND DOOR ACTUATOR RESISTANCE TEST Wire Colors Ohms Red/White & Red/Light Green 5000-7000 Yellow/Light Green & Red/Light Green 3500-6000 Red/White & Yellow/Light Green 250-1500
6. Check Actuator Voltage Turn ignition on. Disconnect blend door actuator harness connector. Check for Dark Blue/Light Green and Orange wires for voltage at harness connector. If battery voltage exists in both circuits, system is operational. If battery voltage does not exist in either circuit, replace Remote Climate Control (RCC) module and retest system.

TEST B - IN-CAR TEMPERATURE SENSOR INOPERATIVE

1. Check For Diagnostic Trouble Codes (DTCs) Simultaneously depress OFF and FLOOR buttons, then press AUTO button within 2 seconds. Display will show a pulse tracer going around the center of the display window for up to 30 seconds while test is running. If DTC 030 and/or 031 are displayed, go to next step. If DTC 030 and/or 031 are not displayed, go to step 3). NOTE: An open sensor will cause a warm air discharge at 65°F (18°C) setting. A shorted sensor will cause a cool air discharge at 85°F (29°C) setting.
2. Check Sensor Resistance Disconnect the in-car temperature sensor connector. Measure resistance between in-car temperature sensor terminals. See «IN-CAR TEMPERATURE SENSOR RESISTANCE TEST»(ref-39943-S40349977592001011200000) table. If resistance is within specifications, go to next step. If resistance is not within specifications, replace sensor and retest system. IN-CAR TEMPERATURE SENSOR RESISTANCE TEST Temperature °F (°C) Ohms 50-68 (10-20) 58,000-37,000 68-86 (20-30) 37,000-24,000 86-104 (30-40) 24,000-16,000
3. Check Power Supply To RCC Module Partially remove Remove Climate Control (RCC) module. Turn ignition on then press AUTO button. Measure voltage of Purple/Orange and Red/White wires at 26-pin RCC harness connector. If battery voltage exists at both wires, go to next step. If battery voltage does not exist at both wires, repair open wire(s) and retest system.
4. Check System Ground Measure resistance between Black/White wire at RCC module harness connector and ground. If resistance is 5 ohms or less, go to next step. If resistance is greater than 5 ohms, replace RCC module and retest system
5. Check RCC Module Start engine. Press MAX A/C or panel-floor button. If the heater or A/C actuate, go to next step. If the heater or A/C do not actuate, replace RCC module and retest system.
6. Check Aspirator Installation Access the aspirator tube and elbow, located behind ICP. Aspirator is attached to the in-car temperature sensor. Verify proper installation of aspirator tube and elbow. If installation is correct, go to next step. If installation is faulty, correct as necessary and retest system.
7. Check In-Car Temp. Sensor Output At RCC Module Turn ignition on. Disconnect in-car temperature sensor. Measure voltage of White/Orange wire at harness connector. If 4.8-5.1 volts exists, go to next step. If 4.8-5.1 volts does not exist, replace RCC module and retest system.
8. Check In-Car Temperature Sensor Circuit Turn ignition off. Measure resistance of White/Orange wire between RCC module and in-car temperature sensor connector. If resistance is 5 ohms or less, go to next step. If resistance is greater than 5 ohms, repair White/Orange wire. Retest system.
9. Check In-Car Temperature Sensor Return Circuit Measure resistance of Pink/Black wire between RCC module connector and in-car temperature sensor connector. If resistance is 5 ohms or less, replace in-car temperature sensor and retest system. If resistance is greater than 5 ohms, repair Pink/Black wire and retest system.

TEST C - AMBIENT AIR TEMP. SENSOR INOPERATIVE

1. Check For Diagnostic Trouble Codes (DTCs) Simultaneously depress OFF and FLOOR buttons, then press AUTO button within 2 seconds. Display will show a pulse tracer going around the center of the display window for up to 30 seconds while test is running. If DTC 040, 041, 042 or 043 are displayed and temperature -40°F(-40°C) or 128°F (53°C) is displayed, go to next step. If DTC 040, 041, 042 or 043 are not displayed and temperature -40°F (-40°C) or 128°F (53°C) is not displayed, go to step 3). Press TEMP button to exit self-diagnostics.
2. Check Sensor Resistance Disconnect the ambient air temperature sensor connector. Measure resistance between ambient air temperature sensor terminals. See «AMBIENT AIR TEMPERATURE SENSOR RESISTANCE TEST»(ref-39943-S42361750042001011200000) table. If resistance is within specifications, go to next step. If resistance is not within specifications, replace sensor and retest system. AMBIENT AIR TEMPERATURE SENSOR RESISTANCE TEST Temperature °F (°C) Ohms 50-68 (10-20) 58,000-37,000 68-86 (20-30) 37,000-24,000 86-104 (30-40) 24,000-16,000
3. Check Voltage At Sensor Connector Turn ignition on then press AUTO button. Disconnect ambient air temperature sensor and bracket. Check voltage between Red/Orange and Pink/Black wires at sensor connector. If voltage is not 4.7-5.1 volts, go to next step. If voltage is 4.7-5.1 volts, go to step 6).
4. Check Red/Orange At RCC Module Connector Ensure ignition is on. Check voltage between Red/Orange and Pink/Black wires at RCC module connector. If voltage is 4.7-5.1 volts, go to next step. If voltage is not 4.7-5.1 volts, replace RCC module. Retest system.
5. Check Red/Orange Wire For Open Circuit Turn ignition off. Connect a jumper wire between ground and Red/Orange wire at ambient air temperature sensor connector. Measure resistance of Red/Orange wire between ground at RCC connector. If resistance is 5 ohms or less, go to next step. If resistance is greater than 5 ohms, repair Red/Orange wire. Retest system.
6. Check Pink/Black Wire For Open Circuit Turn ignition off. Connect a jumper wire between ground and Pink/Black wire at ambient air temperature sensor connector. Measure resistance of Pink/Black wire between ground and RCC module connector. If resistance is 5 ohms or less, replace ambient air temperature sensor. If resistance is greater than 5 ohms, repair Pink/Black wire. Retest system.

TEST D - SUNLOAD SENSOR SHORTED

1. Check For Diagnostic Trouble Codes (DTCs) Simultaneously depress OFF and FLOOR buttons, then press AUTO button within 2 seconds. Display will show a pulse tracer going around the center of the display window for up to 30 seconds while test is running. If DTC 050 or 052 is not displayed, go to next step. If DTC 050 and/or 052 is displayed, go to step 3).
2. Check For Intermittent Short Circuit If DTC 052 was displayed in step 1), go to step 6). If DTC 052 was not displayed, go to step 4).
3. Check Sensor Resistance Disconnect negative battery cable. Disconnect sunload sensor harness connector. Measure resistance across sunload sensor terminals. If zero ohms resistance does not exist, reconnect battery and go to next step. If zero ohms resistance exists, replace shorted sunload sensor and retest system.
4. Check Brown Wire At Sunload Sensor Connector Turn ignition on. Select any A/C function. Partially remove RCC module. Access sunload sensor. Disconnect sunload sensor harness connector. Check Brown wire for voltage at sensor connector. If voltage is not 4.7-6.1 volts, go to next step. If voltage is 4.7-6.1 volts, go to step 7).
5. Check Brown Wire For Short Disconnect Electronic Automatic Temperature Control (EATC) module connector. Access sunload sensor harness connector. Measure resistance between Brown wire at EATC connector and ground. If resistance is greater than 10,000 ohms, go to next step. If resistance is 10,000 ohms or less, repair short in Brown wire and retest system.
6. Check Brown Wire For Open Circuit Ensure ignition is off. Connect a jumper wire between Brown wire terminal at sunload sensor connector and ground. Measure resistance between ground and Brown wire at RCC module connector. If resistance is 5 ohms or less, go to next step. If resistance is greater than 5 ohms, repair open in Brown wire. Retest system.
7. Check Pink/Black Wire For Open Circuit Ensure ignition is off. Measure resistance of Pink/Black wire between RCC module connector and sunload sensor connector. If resistance is 5 ohms or less, go to next step. If resistance is greater than 5 ohms, repair open in Pink/Black wire and retest system.
8. Check Pink/Black Wire For Short To Ground Measure resistance between ground and Pink/Black wire at RCC module connector. If resistance is 10,000 ohms or greater, replace RCC module. Retest system. If resistance is less than 10,000 ohms, repair short to ground in Pink/Black wire.

TEST E - NO MODULE COMMUNICATION

1. Check Fuse No. 13 & 24 Turn ignition off. Remove fuse No. 13 (5-amp) and fuse No. 24 (5-amp) from fuse junction panel. Measure resistance between ground and each fuse terminal. If resistance is greater than 5 ohms, go to next step. If resistance is 5 ohms or less, go to step 3).
2. Check Purple/Orange Wire & Red/White Wire For Short To MD11Ground Remove fuses No. 13 (5-amp) and No. 24 (5-amp) from fuse junction panel. Disconnect Remote Climate Control (RCC) module connector. Measure resistance between ground and Purple/Orange wire. Measure resistance between ground and Red/White wire. If resistance is greater than 10,000 ohms for both circuits, replace RCC module and retest system. If resistance is less than 10,000 ohms for both circuits, repair wire(s) as necessary and retest system.
3. Check For Battery Voltage At RCC Module Turn ignition off. Disconnect RCC module connector. Turn ignition on. Check for battery voltage at Red/White wire and Purple/Orange wire at RCC harness connector. If battery voltage does not exist at both terminals, go to next step. If battery voltage exists at both terminals, go to step 5).
4. Check Red/White Wire & Purple/Orange Wire For Open Turn ignition off. Disconnect instrument panel fuse junction box connector. Disconnect RCC module harness connector. Measure resistance of Red/White wire between junction box connector and RCC module harness connector. Measure resistance of Purple/Orange wire between junction box connector and RCC module harness connector. If resistance is 5 ohms or less for both circuits, go to next step. If resistance is greater than 5 ohms for either circuit, repair wire(s) as necessary. Retest system.
5. Check Black/White Wire For Open Ensure ignition is off. Disconnect RCC module harness connector. Measure resistance of Black/White wire between RCC module harness connector and ground. If resistance is greater than 5 ohms, repair Black/White wire and retest system. If resistance is 5 ohms or less, test module communications network. See the MODULE COMMUNICATIONS NETWORK article in the ACCESSORIES/SAFETY EQUIPMENT section.

TEST G - BLOWER MOTOR INOPERATIVE

1. Check Fuse Check power distribution fuse No. 9 (40-amp) in power distribution box (located on left side of engine compartment). If fuse is blown, go to next step. If fuse is not blown, go to step 4).
2. Check Circuit Turn ignition off. Disconnect connector from blower motor speed controller (located behind glove box). Replace fuse No. 9 (40-amp) in power distribution box. Turn ignition on. Measure voltage between Pink/White and Black wires at blower motor speed controller harness connector. If voltage is greater than 9 volts, go to next step. If voltage is less than 9 volts, check Pink/White and Black wires for open or high resistance. Repair wire(s) as necessary. Retest system.
3. Check Blower Motor Speed Controller Turn ignition off. Reconnect 5-pin harness connector. Turn ignition on. If fuse does not blow, go to next step. If fuse blows, check Orange/Black wire for short. Repair wire if necessary. If Orange/Black wire is okay, replace blower motor speed controller. Retest system.
4. Check Wiring Turn ignition off. Remove Orange/Black wire from blower motor speed controller harness connector. Turn ignition on. Press AUTO button. Press and hold FAN (+) button. If blower operates at high speed, go to next step. If blower does not operate at high speed, go to step 6).
5. Check For Open Circuit Check Orange/Black wire for open circuit between RCC module and blower motor speed controller. Wiggle wire during test. If wire is okay, replace RCC module. If wire is faulty, repair as necessary. Retest system.
6. Check Voltage With Orange/Black wire still disconnected, turn ignition on and press FAN (+) button. Check for voltage at blower motor speed controller harness connector. If voltage is greater than .5 volt, check blower motor. Replace motor if required. If voltage is less than .5 volt, replace blower motor speed controller. Retest system.

TEST H - BLOWER MOTOR OPERATES AT HIGH SPEED AT ALL SPEED SETTINGS

1. Check Blower Operation Disconnect RCC module harness connector. Ground Orange/Black wire. Turn ignition on. If blower operates, go to next step. If blower motor does not operate, replace RCC module. Retest system.
2. Check Blower Motor Speed Controller Turn ignition off. Reconnect RCC module harness connector. Remove Orange/Black wire from blower motor speed controller harness connector. Reconnect harness connector to speed controller. Using a jumper wire, connect Black wire and Orange/Black wire connector terminals at blower motor speed controller harness connector. Turn ignition on. If blower operates, replace blower motor speed controller. If blower motor does not operate, repair open Orange/Black wire.

TEST J - BLOWER MOTOR INOPERATIVE AT HIGH SPEED

1. Check Blower Operation Start engine, select MAX A/C, and set blower speed halfway between high and low speed. Verify that the blower operates. Press and hold FAN (+) button. If blower speed does not increase, go to next step. If blower speed increases, go to «TEST F»(ref-39943-S30995219442001011200000) , step 1).
2. Check Input Voltage Turn ignition off. Disconnect harness connector from blower motor speed controller. Start engine. Press MAX A/C button. Press and hold FAN (+) button. Check voltage between Orange/Black wire and Black wires at blower motor speed controller harness connector. If less than 10 volts exist, go to next step. If greater than 10 volts exist, replace blower motor speed controller. Retest system.
3. Check Voltage Reconnect harness connector from blower motor speed controller. Start engine, select MAX A/C. Press and hold FAN (+) button to obtain full high speed. Measure voltage of Orange/Black wire between RCC module harness connector and ground. If voltage is 10 volts or greater, repair Orange/Black wire between RCC module and blower motor speed controller. If voltage is less than 10 volts, replace RCC module. Retest system.

TEST K - BLOWER MOTOR INOPERATIVE AT LOWER SPEEDS

1. Check Voltage Stability Ensure ignition is off. Disconnect blower motor speed controller harness connector. Connect a 10,000 ohm resistor between Pink/White and Orange/Black wires at connector. Turn ignition on. Set blower motor speed halfway between high and low speed. Check voltage across resistor. Voltage range should be0-5 volts and should not fluctuate. If voltage is as specified, go to next step. If voltage fluctuates, replace RCC module. Retest system.
2. Check Voltage With conditions the same as step 1), press and hold FAN (+) button while observing voltage reading. Voltage should increase. Press and hold FAN (-) button. Voltage should decrease. If voltage varies as specified, replace blower motor speed controller. If voltage does not vary as specified, replace RCC module. Retest system after repair.

TEST L - A/C SYSTEM INOPERATIVE OR DOES NOT OPERATE PROPERLY

1. Check A/C Clutch Operation Start engine and set A/C-heater selector switch to MAX A/C. Ensure battery voltage is at least 12.5 volts. Rotate blower motor switch to HI. If A/C clutch engages, clutch is functioning properly. If clutch does not engage, go to next step.
2. Check A/C Clutch Cycling Pressure Switch Disconnect A/C clutch cycling pressure switch connector. Using a jumper wire, connect A/C clutch cycling pressure switch connector terminals. Start engine and set A/C-heater selector switch to MAX A/C. If clutch engages, go to next step. If clutch does not engage, go to step 4).
3. Check Refrigerant System Pressure Turn engine off. Connect manifold gauge set to A/C service ports. Measure refrigerant pressure. If refrigerant pressure is greater than 50 psi (3.5 kg/cm 2 ), replace A/C clutch cycling pressure switch. If pressure is less than 50 psi (3.5 kg/cm 2 ), check system for refrigerant leaks or low charge. Repair as necessary. Recharge system.
4. Check Voltage At A/C Clutch Cycling Pressure Switch Turn ignition on with engine off. Set A/C-heater selector switch to MAX A/C. Using a voltmeter, check voltage of Purple wire at A/C clutch cycling pressure switch connector. If battery voltage exists, go to next step. If battery voltage does not exist, go to step 16).
5. Check Input Voltage At A/C High Pressure Cut-Off Switch Ensure engine is off and ignition is on. Set A/C-heater selector switch to MAX A/C. Check voltage of Red/Yellow wire at A/C high pressure cut-off switch connector. If battery voltage exists, go to next step. If battery voltage does not exist, repair open in Red/Yellow wire. Retest system.
6. Check A/C High Pressure Cut-Off Switch Resistance Ensure engine is off and ignition is on. Set A/C-heater selector switch to MAX A/C. Using an ohmmeter, measure resistance between Red/Yellow wire and Pink/Black wire at A/C high pressure cut-off switch connector. If resistance is 5 ohms or less, go to next step. If resistance is greater than 5 ohms, replace A/C high pressure cut-off switch and retest system.
7. Check For Input Voltage To Constant Control Relay Module MD11(CCRM) Ensure engine is off and ignition is on. Set A/C-heater selector switch to MAX A/C. Check voltage of Pink/Light Blue wire at CCRM connector (located at radiator support). If battery voltage exists, go to next step. If battery voltage does not exist, repair open in Pink/Light Blue wire. Retest system.
8. Check Powertrain Control Module (PCM) Input Voltage From MD11A/C High Pressure Cut-Off Switch Ensure engine is off and ignition is on. Set A/C-heater selector switch to MAX A/C. Measure voltage of Pink/Light Blue wire at PCM connector. If battery voltage exists, go to next step. If battery voltage does not exist, repair open in Pink/Light Blue wire. Retest system.
9. Check CCRM Output To PCM Disconnect PCM connector. Turn ignition on. Set A/C-heater selector switch to MAX A/C. If A/C clutch does not engage, go to next step. If A/C clutch engages, check PCM operation. For PCM diagnostic procedures, see the TESTS W/CODES article in the ENGINE PERFORMANCE section. After repairs, verify A/C system operation.
10. Check Pink/Yellow Wire For Short To Ground Ensure PCM connector is disconnected. Turn ignition off. Measure resistance of Pink/Yellow wire between PCM connector and ground. If resistance is greater than 5 ohms, go to next step. If resistance is 5 ohms or less, repair short to ground in Pink/Yellow wire.
11. Check CCRM Output To A/C Clutch Ensure PCM connector is disconnected, engine is off and ignition is on. Set A/C-heater selector switch to MAX A/C. Measure voltage of Black/Yellow wire at CCRM connector. If battery voltage exists, go to next step. If battery voltage does not exist, replace CCRM. Retest system.
12. Check Voltage Supply To A/C Clutch Ensure engine is off and ignition is on. Set A/C-heater selector switch to MAX A/C. Disconnect A/C clutch connector. Measure voltage of Black/Yellow wire at clutch connector. If battery voltage exists, reconnect PCM connector and go to next step. If battery voltage does not exist, repair open in Black/Yellow wire. Retest system.
13. Check A/C Clutch Ground Circuit Using an ohmmeter, check resistance in Gray/White wire between A/C clutch connector and ground. If resistance is one ohm or less, go to next step. If resistance is greater than one ohm, check for open in Gray/White wire. If wire is okay, replace CCRM. Retest system.
14. Check A/C Clutch Coil Resistance Ensure engine is off and ignition is on. Set A/C-heater selector switch to MAX A/C. Check resistance between terminals of A/C clutch connector. If resistance less than 6 ohms, go to next step. If resistance is 6 ohms or greater, replace A/C clutch coil. Retest system.
15. Check A/C Clutch Coil Current Draw Using an ammeter, check Gray/White wire for current draw at A/C clutch coil connector. If current draw is 2.5-4.5 amps, check clutch air gap. Adjust as necessary and retest system. If current draw is not 2.5-4.5 amps, replace A/C clutch coil and retest system.
16. Check Voltage Supply At Remote Climate Control MD11(RCC) Module Turn ignition on. Measure voltage on Orange wire at RCC module. If battery voltage does not exist, go to next step. If battery voltage exists, go to step 18).
17. Check Fuse No. 6 Check fuse No. 6 at fuse block. If fuse is blown, repair short to ground in Orange wire, Purple wire, Pink/Light Blue wire and/or Red/Yellow wire. Retest system. If fuse is good, repair open in Orange wire and retest system.
18. Check A/C-Heater Selector Switch MAX A/C Position Ensure engine is off and ignition is on. Reconnect A/C-heater selector switch connector. Set A/C-heater selector switch to MAX A/C position. Measure voltage of Purple wire at A/C-heater selector switch connector. If battery voltage exists, go to next step. If battery voltage does not exist, replace A/C-heater selector switch and retest system.
19. Check A/C-Heater Selector Switch A/C Position Ensure engine is off and ignition is on. Set A/C-heater selector switch to A/C. Rotate A/C-heater selector switch to panel/floor, floor/defrost and defrost positions. Measure voltage on Purple wire at A/C-heater selector switch connector at each switch position. If battery voltage exists at each position, repair open in Purple wire and retest system. If battery voltage does not exist in each position, replace integrated control panel and retest system.

VACUUM SYSTEM TEST

Start engine. Slowly press each of following mode control (manual override) buttons, in turn: MAX A/C, VENT, panel-floor, floor, floor-defrost and F-DEF (front defrost). As each button is pressed, listen for hissing sound from control panel.

A momentary hissing sound, as each button is pressed, indicates vacuum is available at control panel. If hissing sound is continuous, it indicates a large vacuum leak somewhere in system, but not necessarily at control panel. If no hissing sound is heard, check for kinked, pinched or disconnected vacuum supply hose. (Схема №3) Ensure check valve between intake manifold and vacuum reservoir is functioning properly.