A/c-Heater System - Automatic Oldsmobile Eighty-Eight IX

DESCRIPTION

The Electronic Climate Control (ECC) system automatically regulates and maintains selected in-vehicle temperatures from maximum COOL of 65°F (18°C), 60°F (16°C) on Oldsmobile, to maximum WARM of 85°F (30°C), 90°F (32°C) on Oldsmobile. The microprocessor automatically regulates fan speed, air inlet positions and air outlet positions. The control panel has a digital display for temperature selection. (Scheme 1) Individual vacuum operated mode valve actuators are used to position A/C-heater mode doors to maintain set temperature.

OPERATION

The A/C control panel buttons transfers control selection to a microprocessor inside control panel. The microprocessor executes desired selection through power transistors, and displays the last selection ordered through Light Emitting Diodes (LEDs) in the faceplate when ignition is turned on.

The microprocessor sends signals to a programmer and blower motor control module. The programmer positions the mode doors, and the blower motor control module provides control over blower motor speed. The programmer converts electrical signals into vacuum commands to control mode doors. Programmer uses an electrical motor which sends signals to 4 solenoids for vacuum control. A feedback potentiometer in the programmer informs the microprocessor of mode door positions.

Scheme 1

CONTROL PANEL

The control panel is housed in a plastic box mounted in instrument panel. The control panel faceplate contains A/C-heater mode control, blower fan control and temperature setting switches.

In-car temperatures are controlled in all mode positions. A timer delays blower operation for approximately 3 minutes after ignition is turned on and control panel has been set to either HTR or BI-LEV modes. Blower fan will start immediately in DEF mode.

OFF Mode

With this mode selected, system will not let blower motor or A/C compressor run. This position forces recirculation door open to outside air and forces all air out floor ducts.

HTR Mode

In this mode, system will not let A/C compressor run. It will adjust to temperature range selected. The only automatic operation in this mode is regulating temperature door position and fan speed. If engine is cold, blower operation will be delayed.

ECON Mode

In this mode, A/C compressor will not run. System will try to adjust to temperature range through outside air and heated air. This mode is automatic and determines blower speed and air outlet positions.

AUTO Mode

In this mode everything is controlled automatically by various inputs. System will adjust to temperature range selected. This mode also has the capability of any fan blower speed, any air inlet position, and any air outlet position required to reach and maintain selected temperature.

BI-LEV Mode

In this mode, system will let air enter vehicle only through bi-level heater and A/C outlets. This mode is automatic in that it can bring vehicle to temperature range selected, and control fan blower speed and air inlet by interpreting various input signals.

DEF Mode

In this mode, system will run blower at a fixed high rate of speed, unless LO or AUTO are selected, and air will exit out defroster openings. System is automatic in this setting as A/C compressor and air inlet are controlled automatically based on various input signals. This is the only mode in automatic operation where there will be no blower delay when heat is called for.

R DEFOG Mode

The programmer sends a signal to the rear defogger relay which turns on the heating grid in the rear glass. Relay will be energized for 10 minutes. Selecting R DEFOG more than once will add 5 minutes for each time selected.

PROGRAMMER

The ECC programmer is mounted on right side of A/C-heater box, and operates mode door to blend heated and cooled air. ECC programmer contains an electric motor, feedback potentiometer and 4 vacuum solenoids. Signals from A/C-heater control unit causes electric motor to rotate, energizing or de-energizing solenoids. This applies or releases vacuum to mode door actuators. (Scheme 2)

Scheme 2

SENSORS

An in-car temperature sensor and an outside (ambient) air temperature sensor are used to provide basic control inputs for system. Both are thermistor type and develop a low voltage signal which is directly proportional to actual temperature readings.

The in-car sensor is mounted in the dash, above glove compartment. The outside air sensor is located on the radiator support, next to power steering cooling line. These sensors provide basic control inputs for automatic operation.

Oldsmobile models also use a sunload sensor. This sensor informs the ECC control panel of direct sun light entering vehicle. Sensor is mounted under passenger side defroster grille.

ASPIRATOR

The aspirator is mounted on the A/C-heater box. A small amount of air from cold air portion of A/C-heater box is drawn through a hose creating a small vacuum. This vacuum causes passenger compartment air to be drawn across the in-car sensor. This sensor then signals the control panel to adjust temperature as necessary to maintain selected temperature.

BLOWER MOTOR CONTROL MODULE

The blower motor control module is located in the blower motor air stream in the engine compartment. The blower control feeds current to the blower motor through a variable range so blower speed can be varied to many different speeds.

A/C Select Relay

The microprocessor in the control panel energizes the A/C select relay when AUTO, BI-LEV or DEF mode is selected. This relay is located in the relay center in passenger compartment right kick panel.

A/C Compressor Control Relay

The Electronic Control Module (ECM) can override all other controls and cause A/C compressor clutch to disengage. If ECM determines less load on the engine is needed, ECM will remove ground path to this relay interrupting power to A/C compressor clutch. This relay is mounted on firewall, behind A/C accumulator.

Pressure Cycling Switch

This switch maintains correct evaporator temperature. When low side refrigerant temperature drops below 25 psi (1.8 kg/cm 2 ), this normally closed switch opens and interrupts battery voltage to A/C compressor clutch. The pressure cycling switch is mounted on A/C accumulator.

A/C High Pressure Cut-Out Switch

This switch provides compressor protection by opening the compressor clutch circuit if high side pressure exceeds 430 psi (30.2 kg/cm 2 ). When pressure falls below 200 psi (14.1 Kg/cm 2 ), switch will close allowing compressor operation.

PROGRAMMER LINK ROD

1. Remove glove box. Pull link rod from retainer on programmer output crank. Start vehicle and set ECC control panel to maximum heating and HI blower speed. If outside temperature is above 90°F (33°C), disconnect in-car temperature sensor.
2. Allow a minimum of 45 seconds for programmer to reach full heating position. Move mode door to maximum heat position and snap link rod into programmer output crank retainer. Cycle ECC control panel from maximum heating to maximum cooling and observe link rod for smooth operation. (Scheme 3)

Scheme 3

TROUBLE SHOOTING

To accurately trouble shoot system, vehicle must be at running temperature and at idle. Outside air temperature must be 60°F 16°C) or higher. Enter self-diagnostics and observe trouble codes. If a trouble code of "00" appears, system has NOT detected any faults.

If ECC programmer is removed for testing, ensure programmer is held level. Solenoid valves may not close properly if not level

Oldsmobile

To enter diagnostic mode, press "OUTS TEMP" button then press "BI-LEV" button. Hold both button for 3 seconds. A "00" will be displayed indicating entry into diagnostic mode. (Scheme 1) To exit diagnostic mode, press "OFF" button. To clear codes from memory, remove fuse No. 11.

TROUBLE CODES

OLDSMOBILE & PONTIAC TROUBLE CODES

BLOWER MOTOR INOPERATIVE

1. Disconnect electrical connector at blower motor. Turn ignition on, set control panel to "ECON" and blower motor speed to HI". Using a voltmeter, measure voltage at blower motor Purple wire and ground.
2. If battery voltage is present, but blower motor does not run, replace blower motor. If battery voltage is NOT present, check Purple wire for open or short to ground. If Purple wire is okay, check Black (ground) wire for an open. Check that ground wire is clean and tight. If blower motor still does not run, go to BLOWER MOTOR CONTROL MODULE.

1. Disconnect electrical connector at blower control unit. Turn ignition on, set control panel to "ECON" and blower motor speed to "HI". Set control panel temperature to maximum cooling and ensure outside temperature is above 60°F (16°C).
2. Using a voltmeter, measure voltage between blower motor control module Red wire and ground, Red wire and Black wire, and Gray/Black wire and ground. If battery voltage is present for each test but blower motor does not run, replace blower motor control module.
3. If battery voltage is not present in step 2), check fusible link and Red wire for open. Check Black ground wire for open. Check Gray/Black wire for open. If all wires are okay, go to A/C-HEATER CONTROL PANEL.

A/C-HEATER CONTROL PANEL

1. Turn ignition on. Set control panel to "ECON" and blower motor speed to "HI". Set control panel temperature to maximum cooling. Ensure outside temperature is above 60°F (16°C).
2. Using a voltmeter, measure voltage at A/C-heater control panel Orange wire and ground, Brown wire and ground, and Brown wire and Black wire. If battery voltage is present for each test, but blower motor does not run, replace blower motor control module.
3. If battery voltage is not present in Orange wire, check fuse No. 11 and Orange wire for open. If battery voltage is not present for Brown wire to ground, check fuse No. 7 and Brown wire for open. If battery voltage is not present for Brown wire to Black wire, Check Black wire for open.
4. Check voltage between Light Green/Black wire and ground. If voltage is 7-10 volts, wire is okay. If not, check Light Green/Black wire for short to ground. If wire is okay, replace A/C-heater control panel.
5. Check for battery voltage between Purple wire and ground. If battery voltage is not present, check for open or short to ground in Purple wire between fusible link and A/C-heater control panel. If wire is okay, replace A/C-heater control panel.
6. Change blower speed from "HI" to "LO". Using a voltmeter, check for 2-3 volts between Light Green/Black wire and ground. If voltage reading is not correct, check Light Green/Black wire for short to ground. If wire is good, replace A/C-heater control panel.
7. With blower speed still on "LO", check for 3-5 volts between Purple wire and ground. If voltage reading is not correct, check for open or short to ground in Purple wire between fusible link G" and A/C-heater control panel. If wire is okay, replace A/C-heater control panel.

A/C CUT-OUT RELAY

1. Disconnect electrical connector at relay. Turn ignition on. Set temperature to 65°F. Ensure outside temperature is above 60°F 16°C).
2. Using a voltmeter, check for battery voltage between Pink/Black wire and ground. If battery voltage is not present, check fuse No. 5, and check for open in Pink/Black wire.
3. Check for battery voltage between Light Blue wire and ground. If battery voltage is not present, check for an open in Light Blue wire. If voltage readings are correct, see A/C SELECT RELAY.
4. Install a jumper wire between Light Blue wire and Dark Green wire in cut-out relay connector. The A/C compressor clutch should engage. If not, see ECM A/C COMPRESSOR CONTROL in the COMPUTERIZED ENGINE CONTROL section.

1. Turn ignition on. Set control panel to "AUTO" and temperature to 65°F. Ensure outside temperature is above 60°F (16°C).
2. Using a voltmeter, check for battery voltage between each of 2 Brown wires and ground. If reading is not correct, check fuse No. 7 and Brown wires for open.
3. Change control panel setting from "AUTO" to "OFF". Install a jumper wire between Brown wire and Light Green wire. Using a voltmeter, check for battery voltage between Light Blue wire and ground. If voltage is not present, check for open A/C pressure cycling switch and/or open A/C high pressure cut-out switch.

COMPRESSOR CLUTCH CONTROL

1. Turn ignition on. Set control panel to "AUTO" and set temperature to 65°F. Ensure outside temperature is above 60°F (16°C).
2. Remove A/C select relay and perform tests at connector. Using a test light, check that power exists between Brown and Dark Green/Yellow wires. If power does not exist, check for open in Light Blue/Black and Dark Green/Yellow wires. If wires are okay, replace A/C-heater control panel.
3. Change control panel setting from "AUTO" to "ECON". Using test light, check that power DOES NOT exists between Brown and Dark Green/Yellow wires. If power exists, check for short to ground in Light Blue/Black and Dark Green/Yellow wires. If wires are okay, replace A/C-heater control panel.

AIR-MIX VALVE FEEDBACK

1. Turn ignition on. Set control panel to "AUTO". Using a voltmeter, check for battery voltage between ECC programmer Brown/White wire and ground. If voltage is not present, check for open in Brown/White and Orange/Black wires. If wires are okay, replace A/C-heater control panel.
2. Check for battery voltage between ECC programmer Brown/-White wire and Black wire. If voltage is not present, check Black wire for open.
3. Check for 5 volts between ECC programmer Light Blue wire and ground. If reading is not okay, check Light Blue wires for open. If wires are okay, replace ECC programmer.
4. Connect voltmeter between ECC programmer Light Blue wire and ground. Check that voltage reading varies from .4 volt to 5 volts when changing temperature setting from maximum cooling to maximum heating. If voltage reading DOES NOT vary, replace ECC programmer.

AIR-MIX VALVE MOTOR

1. Turn ignition on. Set control panel to "AUTO". Set control panel temperature to 65°F. Ensure outside temperature is above 60°F (16°C).
2. Using a voltmeter, check for 8 volts between ECC programmer Black wire and ground. If reading is not okay, check Dark Blue wire and Black wire for open or short to ground. If wires are okay, replace A/C-heater control panel.
3. Check for 8 volts between ECC programmer White/Black wire and ground. If reading is not okay, check ECC programmer and A/C-heater control panel White/Black wires for open or short to ground. If wires are okay, replace A/C-heater control panel.
4. Connect voltmeter between ECC programmer Black wire and ground. Change temperature setting to maximum heating. Observe voltmeter while changing temperature. Voltage should drop to less than .5 volt when maximum heating is reached. If reading is NOT okay, replace A/C-heater control panel.
5. Connect voltmeter between ECC programmer White/Black wire and ground. Change temperature setting to maximum heating. Observe voltmeter while changing temperature. Voltage should increase to 8-9 volts when maximum heating is reached. If reading is NOT okay, replace A/C-heater control panel.
6. Connect voltmeter between ECC program Black wire and ground. Change temperature setting to maximum cooling. Observe voltmeter while changing temperature. Voltage should increase to 8-9 volts when maximum cooling is reached. If reading is NOT okay, replace A/C-heater control panel.
7. Connect voltmeter between ECC programmer White/Black wire and ground. Change temperature setting to maximum cooling. Observe voltmeter while changing temperature. Voltage should drop to less than .5 volt when maximum cooling is reached. If reading is NOT okay, replace A/C-heater control panel.

IMPROPER AIRFLOW

1. Turn ignition on. Set control panel to "OFF" and control panel temperature to 65°F. Ensure outside temperature is above 60°F 16°C).
2. Using a voltmeter, check for 5 volts between A/C-heater control panel Dark Green/White and ground. If reading is NOT okay, A/C-heater control panel and ECC programmer Dark Green/White wires for an open. If wires are okay, replace ECC programmer.
3. Check for 5 volts between A/C-heater control panel Yellow/Black wire and ground. If reading is NOT okay, check A/C-heater control panel and ECC programmer Yellow/Black wires for an open. If wires are okay, replace ECC programmer.
4. Change control panel setting to "UPPER". Using a voltmeter, check for 5 volts between terminal A/C-heater control panel Dark Green/White wire and ground. If reading is NOT okay, check A/C-heater control panel and ECC programmer Dark Green/White wires for an open. If wires are okay, replace ECC programmer.
5. Check for .5 volt maximum between A/C-heater control panel Yellow/Black wire and ground. If reading is NOT okay, replace A/C-heater control panel.
6. Check for .5 volt maximum between A/C-heater control panel Brown/White wire and ground. If reading is NOT okay, replace A/C-heater control panel.
7. Change control panel setting to "BI-LEV". Using a voltmeter, check for 5 volts between A/C-heater control panel Dark Green/White wire and ground. If reading is NOT okay, check A/C-heater control panel and ECC programmer Dark Green/White wires for an open. If wires are okay, replace ECC programmer.
8. Check for .5 volt maximum between A/C-heater control panel Yellow/Black wire and ground. If reading is NOT okay, replace A/C-heater control panel.
9. Check for approximately 3.5 volts maximum between A/C-heater control panel Brown/White wire and ground. If reading is NOT okay, replace A/C-heater control panel.
10. Change control panel setting to "DEF". Using a voltmeter, check for 5 volts between A/C-heater control panel Dark Green/White wire and ground. If reading is NOT okay, check A/C-heater control panel and ECC programmer Dark Green/White wires for an open. If wires are okay, replace ECC programmer.
11. Check for 5 volts between A/C-heater control panel Yellow/Black wire and ground. If reading is NOT okay, replace A/C-heater control panel.
12. Check for .5 volt maximum between A/C-heater control panel Brown/White wire and ground. If reading is NOT okay, replace A/C-heater control panel.

AMBIENT TEMPERATURE SENSOR

1. Disconnect connector at sensor. Turn ignition on. Using a voltmeter, check for 5 volts between Yellow wire and ground. If reading is NOT okay, check A/C-heater control panel White wire and sensor Yellow wire for open or short to ground. If wires are okay, replace A/C-heater control panel.
2. Check for 5 volts between Yellow and Black (ground) sensor wires. If reading is NOT okay, repair open in Black sensor wire. If sensor voltage readings are correct, check sensor resistance. Using an ohmmeter, check that resistance across sensor terminals is between 2000-4500 ohms. If resistance values are not correct, replace sensor.

IN-CAR TEMPERATURE SENSOR

1. Disconnect connector at sensor and turn ignition on. Using a voltmeter, check for 5 volts between Dark Green wire and ground. If reading is NOT okay, check Dark Green wire for open or short to ground. If wire is okay, replace A/C-heater control panel.
2. Check for 5 volts between Dark Green and Black (ground) wires. If reading is NOT okay, repair open in Black sensor wire. If sensor voltage readings are correct, check sensor resistance. Using an ohmmeter, check that resistance across sensor terminals is between 2000-4500 ohms. If resistance values are not correct, replace sensor.

1. Disconnect connector at sensor. Turn ignition on. Using a voltmeter, check for 5 volts between Light Blue/Yellow wire and ground. If reading is NOT okay, check Light Blue/Yellow wire for open or short to ground. If wire is okay, replace A/C-heater control panel.
2. Check for 5 volts between Light Blue/Yellow and Black/White (ground) wires. If reading is NOT okay, repair open in Black/White sensor wire. If sensor voltage readings are correct, replace sensor.

* PLEASE READ FIRST *

Note. For components not covered in this article see appropriate article: For Delta 88 see A/C-HEATER SYSTEM - MANUAL For Ninety-Eight see A/C-HEATER SYSTEM - MANUAL

Removal & Installation

1. Disconnect negative battery cable. Remove control panel trim plate. Remove 4 screws from control panel.
2. Pull control panel out to access connectors. Disconnect connectors and vacuum hoses. Remove control panel. To install, reverse removal procedure.

Note. The control panel and programmer are not serviceable. If for any reason they must be replaced, an exchange unit must be obtained from an A/C Delco Service Center.

Disconnect negative battery cable. Disconnect connector at module. Remove blower motor control module retaining screws. Remove blower motor control module. To install, reverse removal procedure.

1. Disconnect negative battery cable. Remove passenger side sound insulator. Remove glove box. Remove screw securing link shield and remove shield.
2. Disconnect temperature valve link rod. Disconnect connectors and vacuum hoses. Remove 3 programmer retaining screws and remove programmer. To install, reverse removal procedure. Check programmer link rod adjustment. See ADJUSTMENTS in this article.

Remove ECC programmer. Unsnap programmer case and remove cover. Remove programmer motor mounting screws. Disconnect connectors and remove programmer motor. To install, reverse removal procedure.

Electronic Climate Control Wiring Diagram. Scheme 4