A/c-Heater System - Automatic: Other Chrysler LHS I

Automatic Mode

In this mode, the system automatically controls temperature, fan speed, and mode setting. Light Emitting Diodes (LED) in push buttons indicate active mode.

Semi-Automatic Mode

If blower/fan speed is manually selected, the system will automatically control temperature and mode setting.

Manual Mode

If both blower/fan speed and mode are manually selected, or if full heat or full cooling is selected, both blower/fan speed and temperature will be controlled according to selected knob position.

A/C Button

Pressing A/C button turns A/C system on or off. (Scheme 6) When A/C button is pressed, a signal is sent to Body Control Module (BCM) to indicate button status.

Blower Control Knob

In semi-automatic mode, blower/fan speed is controlled by rotating blower control knob.

Temperature Control Knob

Temperature control knob allows user to select interior temperature. Clockwise rotation increases temperature setting. Counterclockwise rotation decreases temperature.

Mode Controls

There are 10 buttons for selection of air delivery mode: automatic, off, floor, mix, A/C, front defrost, panel (vent), bi-level, recirculated air, and rear defogger.

Scheme 6

BLOWER MOTOR POWER MODULE

Blower motor power module controls blower motor speed through a signal received from BCM.

EVAPORATOR TEMPERATURE SENSOR

Evaporator temperature sensor provides one of the inputs required to control A/C compressor clutch. Sensor monitors evaporator temperature and sends signal to the BCM to turn off the compressor before evaporator freeze-up occurs.

SUN LOAD SENSOR

Sun load sensor is located on top of the instrument panel. Sun load sensor senses level of sunlight entering vehicle to determine whether additional cooling is needed.

IN-VEHICLE TEMPERATURE SENSOR

In-vehicle temperature sensor is located behind right side of instrument panel. It sends a signal to the body controller, which is used to make temperature adjustments. If sensor is open or shorted, digital display will turn off and system will revert to manual operation.

AMBIENT TEMPERATURE SENSOR

Ambient temperature sensor is located inside left front bumper beam. This thermistor monitors outside air temperature. BCM uses information provided by ambient sensor to regulate blower speed, temperature offsets, evaporator temperature, and mode control. If sensor fails, battery temperature input signal is used as back-up.

AUTOMATIC TEMPERATURE CONTROL RECALIBRATION

The Automatic Temperature Control (ATC) system must be recalibrated if the battery is disconnected or loses power. If it is not, the system will not operate properly. To recalibrate the system

1. When the battery power is restored, disconnect the electrical connector near the battery. Leave disconnected for at least 15 minutes. (Scheme 7)
2. Reconnect the connector. Start and run the engine for at least one minute. The ATC system is now calibrated

Scheme 7

CLIMATE TESTS Mode

This function allows user to perform partial charge and A/C-ON tests.

CLIMATE FAULTS Mode

This function allows user to perform engine and body computer fault tests and Automatic Temperature Control (ATC) head/panel tests.

CLIMATE STATE Mode

This function allows user to read states or values of a variety of sensors, inputs/outputs, monitors, and custom displays. This function also permits identification of Powertrain Control Module (PCM), Body Control Module (BCM), and ATC software versions.

CLIMATE ACTUATORS Mode

This function allows user to change engine RPM and exercise A/C-heater system relays and actuators, as well as in-vehicle temperature aspirator.

REPAIRING DRB BLANK SCREEN

1. If DRB screen is blank, turn ignition off and disconnect DRB from Data Link Connector (DLC). Using DVOM, measure voltage at DLC terminal No. 2 (Pink wire). If voltage is less than 10 volts, check fuse No. 13 and/or repair Pink wire circuit between battery and DLC. If voltage is greater than 10 volts, go to next step.
2. Using DVOM, measure resistance between DLC terminal No. 6 (Black/Light Green wire) and ground. If resistance is greater than 20 ohms, repair open Black/Light Green wire ground circuit. If resistance is less than 20 ohms, go to next step.
3. If DRB screen is still blank, substitute a different cable, cartridge or DRB until condition is corrected.

DRB Volt-Ohmmeter

1. To access DRB volt-ohmmeter mode, connect Red volt/ohmmeter test lead to Red port, located on right-top side of DRB.
2. To use DRB voltmeter, press VOLT/OHM key once. Touch test probe to connector or wire to be measured. Read voltage on DRB display. When voltage testing is complete, press VOLT/OHM key 3 times to exit voltmeter mode.
3. To use DRB ohmmeter, press VOLT/OHM key twice. Touch test probe to connector or wire to be measured. Read resistance to circuit ground on DRB display. When resistance testing is complete, press VOLT/OHM key twice to exit ohmmeter mode.

DRB Continuity Meter

Press VOLT/OHM key 3 times. Display will read NO CONTINUITY. Touch test probe to connector or wire to be measured. Read continuity on DRB display. When continuity testing is complete, press VOLT/OHM key once to exit continuity meter.

IDENTIFYING VEHICLE EQUIPMENT & SYSTEM PROBLEMS

1. Turn ignition off. Connect DRB to Data Link Connector (DLC). see scheme 5 Turn ignition on. If DRB screen is blank, see REPAIRING DRB BLANK SCREEN.
2. With DRB, select BODY under SELECT SYSTEM and then BODY COMPUTER. If DRB does not display BUS OPERATIONAL message, check body control computer for bus failure messages. See the TESTS W/CODES article in the ENGINE PERFORMANCE section. If BUS OPERATIONAL message is displayed, go to next step.
3. Select body controller. Select ATC system. If DRB displays NO RESPONSE, go to TEST 113A: BATTERY POWER TO MODULE DISCONNECTED. If NO RESPONSE is not displayed, go to TEST 2A: AUTOMATIC TEMPERATURE CONTROL.

Note. See TEST 2A and TEST 113A in TROUBLE SHOOTING.

Vehicle Preparation

1. Set parking brake. Set shift lever to Park position. Start and idle engine at 700 RPM. Set A/C controls to outside air, panel (vent) mode, full cool, and A/C button on. Set blower to high speed. Open windows. Set recirculated air button to off position.
2. Operate system for a few minutes to allow system to stabilize. Place a piece of cardboard over front part of condenser. This will stop cooling fans from alternating speeds and maintain A/C pressure at 260 psi (18.3 kg/cm 2 ).

Using DRB

Attach Thermocouple (80PK-1A) to liquid line, as close to condenser outlet as possible. Connect DRB to data link connector. see scheme 5 Set DRB to LH CLIMATE CONTROL, SYSTEM TEST, and PARTIAL CHARGE TEST. The correct liquid line temperature range is calculated by DRB.

Using Manifold Gauge Set

1. Attach clamp-on thermocouple to liquid line, as close to condenser outlet as possible. Connect gauge set to high side and low side connectors.
2. Note discharge pressure and liquid line temperature. Use REFRIGERANT CHARGE LEVEL table to determine if system is undercharged or overcharged.

Charge Level Corrections

Depending on system charge condition, make corrections 2 ounces at a time. After each correction, recheck readings to verify proper charge. Total system capacity is 28 ounces.

REFRIGERANT CHARGE LEVEL

1. Locate in-vehicle temperature sensor aspirator behind name plate, on right side of instrument panel. Turn ignition on. Press OFF button on A/C-heater control panel. Place a small piece of tissue paper in front of sensor opening.
2. If paper sticks to sensor opening, in-vehicle temperature sensor aspirator is working properly. If tissue paper does not stick, inspect in-vehicle temperature sensor. Go to TEST 9A: ATC ASPIRATOR & IN-CAR TEMPERATURE SENSOR to test sensor and aspirator. See TROUBLE SHOOTING.
3. Inspect for presence and condition of 2 foam seals. One seal is located behind name plate. The other is located near right center duct opening. Replace or repair seals as necessary.

Ensure sensor is not covered by papers, windshield wipers, top cover, or stickers on windshield installed in front of sensor. Go to TEST 3A to test sensor. See TROUBLE SHOOTING .